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Fossa (animal)
Encyclopedia
The fossa is a cat
-like, carnivorous mammal
that is endemic to Madagascar
. It is a member of the Eupleridae
, a family
of carnivora
ns closely related to the mongoose
family (Herpestidae). Its classification
has been controversial because its physical traits resemble those of cats
, yet other traits suggest a close relationship with viverrids (most civets and their relatives). Its classification, along with that of the other Malagasy carnivores, influenced hypotheses about how many times mammalian carnivores have colonized the island. With genetic studies demonstrating that the fossa and all other Malagasy carnivores are most closely related to each other (forming a clade
, recognized as the family Eupleridae), carnivorans are now thought to have colonized the island once around 18 to 20 million years ago.
The fossa is the largest mammalian carnivore
on the island of Madagascar and has been compared to a small cougar. Adults have a head-body length of 70–80 cm (27.6–31.5 in) and weigh between 5.5 kilogram, with the males larger than the females. It has semi-retractable claws and flexible ankles that allow it to climb up and down trees head-first, and also support jumping from tree to tree. The fossa is unique within its family for the shape of its genitalia, which share traits with those of cats and hyena
s.
The species is widespread, although population densities
are usually low. It is found solely in forested habitat, and actively hunts both by day and night. Over 50% of its diet consists of lemur
s, the endemic primate
s found on the island; tenrecs, rodent
s, lizards, birds, and other animals are also documented as prey. Mating usually occurs in trees on horizontal limbs and can last for several hours. Litters range from one to six pups, which are born blind and toothless (altricial
). Infants wean after 4.5 months and are independent after a year. Sexual maturity
occurs around three to four years of age, and life expectancy in captivity is 20 years. The fossa is listed as "Vulnerable
" by the International Union for Conservation of Nature (IUCN). It is generally feared by the Malagasy people and is often protected by their taboo
, known as fady. The greatest threat to the species is habitat destruction
.
is hidden by its anal pouch, from the Ancient Greek
words crypto- "hidden", and procta "anus". The species name ferox is the Latin
adjective "fierce" or "wild." Its common name
is spelled fossa in English or fosa in Malagasy
, the Austronesian language
from which was taken. The word is similar to posa (meaning "cat
") in the Iban language
(another Austronesian language) from Borneo
, and both terms may derived from trade languages from 1600s. However, an alternative etymology
suggests a link to another word that comes from Malay
: pusa refers to the Malayan weasel
(Mustela nudipes). The Malay word pusa could have become posa for cats in Borneo while in Madagascar the word could have become fosa to refer to the fossa.
. The common name is the same as the generic name of the Malagasy civet (Fossa fossana), but they are different species. Because of shared physical traits with civet
s, mongoose
s, and cats (Felidae
), its classification
has been controversial. Bennett originally placed the fossa as a type of civet
in the family Viverridae, a classification that long remained popular among taxonomists. Its compact braincase, large eye sockets
, retractable claws, and specialized carnivorous dentition
have also led some taxonomists to associate it with the felids. In 1939, William King Gregory
and Milo Hellman placed the fossa in its own subfamily within Felidae, the Cryptoproctinae. George Gaylord Simpson
placed it back in Viverridae in 1945, still within its own subfamily, yet conceded it had many cat-like characteristics.
In 1993, Géraldine Veron and François Catzeflis published a DNA hybridization study suggesting that the fossa was more closely related to mongooses (family Herpestidae) than to cats or civets. However, in 1995, Veron's morphological
study once again grouped it with Felidae. In 2003, molecular phylogenetic studies using nuclear
and mitochondrial genes
by Anne Yoder and colleagues showed that all native Malagasy carnivorans share a common ancestry that excludes other carnivores (meaning they form a clade
, making them monophyletic
) and are most closely related to Asian and African Herpestidae. To reflect these relationships, all Malagasy carnivorans are now placed in a single family, Eupleridae
. Within Eupleridae, the fossa is placed in the subfamily Euplerinae
with the falanouc
(Eupleres goudoti) and Malagasy Civet, but its exact relationships are poorly resolved.
An extinct relative of the fossa was described in 1902 from subfossil
remains and recognized as a separate species, Cryptoprocta spelea
, in 1935. This species was larger than the living fossa (with a body mass estimate roughly twice as great), but otherwise similar. Across Madagascar, people distinguish two kinds of fossa—a large fosa mainty ("black fossa") and the smaller fosa mena ("reddish fossa")—and a white form has been reported in the southwest. It is unclear whether this is purely folklore or individual variation—related to sex, age or instances of melanism
and leucism—or whether there is indeed more than one species of living fossa.
-like head, relatively longer than that of a cat, although with a muzzle that is broad and short, and with large but rounded ears. It has medium brown eyes set relatively wide apart with pupils that contract to slits. Like many carnivorans that hunt at night, its eyes reflect light
; the reflected light is orange in hue.
Its head-body length is 70–80 cm (27.6–31.5 in) and its tail is 65–70 cm (25.6–27.6 in) long. There is some sexual dimorphism
, with adult males (weighing 6.2–8.6 kg; 14–19 lb) being larger than females (5.5–6.8 kg; 12–15 lb). Smaller individuals are typically found north and east on Madagascar, while larger ones to the south and west. Unusually large individuals weighing up to 20 kg (44.1 lb) have been reported, but there is some doubt as to the reliability of the measurements. The fossa can smell, hear, and see well. It is a robust animal and illnesses are rare in captive fossas.
Both males and females have short, straight fur that is relatively dense and without spots or patterns. Both sexes are generally a reddish-brown dorsally and colored a dirty cream ventrally. When in rut, they may have an orange coloration to their abdomen
from a reddish substance secreted by a chest gland
secretions, but this has not been consistently observed by all researchers. The tail tends to be lighter in coloration than the sides. Juveniles are either gray or nearly white.
Several of the animal's physical features are adaptions to climbing through trees. It uses its tail to aid in balance and has semi-retractable claws that it uses to climb trees in its search for prey. It has semiplantigrade
feet, switching between a plantigrade-like gait (when arboreal) and a digitigrade
-like one (when terrestrial
). The soles of its paws are nearly bare and covered with strong pads. The fossa has very flexible ankles that allow it to readily grasp tree trunks so as to climb up or down trees head first or to leap to another tree. Captive juveniles have been known to swing upside down by their hindfeet from knotted ropes.
The fossa has several scent gland
s, although the glands are less developed in females. Like herpestids it has a perianal skin gland inside an anal sac which surrounds the anus like a pocket. The pocket opens to the exterior with a horizontal slit below the tail. Other glands are located near the penis or vagina, with the penile glands emitting a strong odor. Like the herpestids, it has no prescrotal glands.
One of the more interesting physical features of this species is its external genitalia. Males have an unusually long penis and baculum
(penis bone), reaching to between its forelegs when erect. The glans
extends about halfway down the shaft and is spiny except at the tip. In comparison, the glans of felids is short and spiny, while that of viverrids is smooth and long. The female fossa exhibits transient masculization, starting at about 1–2 years of age, developing an enlarged, spiny clitoris
that resembles a male's penis. The enlarged clitoris is supported by an os clitoridis, which decreases in size as the animal grows. Females do not have a pseudo-scrotum, but they do secrete an orange substance that colors their underparts, much like the secretions of males. Hormone levels (testosterone
, androstenedione
, dihydrotestosterone
) do not seem to play a part in this transient masculization, as those levels are the same in masculinized juveniles and nonmasculinized adults. It is speculated that the transient masculization either reduces sexual harassment of juvenile females by adult males, or reduces aggression from territorial females. While females of other mammal species (such as the spotted hyena
) have a pseudo-penis
, none of them are known to have theirs diminish in size as the animal grows.
, including teeth shape and facial
portions of the skull, the tongue, and the digestive tract, typical of its exclusively carnivorous diet. The remainder of the skull most closely resembles those of genus Viverra
, while the general body structure is most similar to that of various members of Herpestidae. The permanent dentition is (three incisor
s, one canine
, three or four premolar
s, and one molar
on each side of both the upper and lower jaws), with the deciduous formula being similar but lacking the fourth premolar and the molar. The fossa has a large, prominent rhinarium
similar to that of viverrids, but has comparatively larger, round ears, almost as large as those of a similarly sized felid. Its facial vibrissae
(whiskers) are long, with the longest being longer than its head. Like some mongoose genera, particularly Galidia (which is now in the fossa's own family, Eupleridae) and Herpestes
(of Herpestidae), it has carpal vibrassae as well. Its claws are retractile, but unlike those of Felidae species, they are not hidden in skin sheaths. It has three pairs of nipples (one inguinal, one ventral, and one pectoral).
s, and the southern spiny forests
, it is seen more frequently in humid than in dry forests. This may be because the reduced canopy in dry forests provides less shade, and also because the fossa seems to travel more easily in humid forests. It is absent from areas with the heaviest habitat disturbance and, like most of Madagascar's fauna, from the central high plateau of the country.
The fossa has been found across several different elevational gradients in undisturbed portions of protected areas throughout Madagascar. In the Réserve Naturelle Intégrale d'Andringitra, evidence of the fossa has been reported at four different sites ranging from 810 to 1625 m (2,657.5 to 5,331.4 ft). Its highest known occurrence was reported at 2000 m (6,561.7 ft); its presence high on the Andringitra Massif
was subsequently confirmed in 1996. Similarly, evidence has been reported of the fossa at the elevational extremes of 440 m (1,443.6 ft) and 1875 m (6,151.6 ft) in the Andohahela National Park
. The presence of the fossa at these locations indicates its ability to adapt to various elevations, consistent with its reported distribution in all Madagascar forest types.
The fossa is active during both the day and the night and is considered cathemeral
; activity peaks may occur early in the morning, late in the afternoon, and late in the night. The animal generally does not reuse sleeping sites, but females with young do return to the same den. The home ranges of male fossas in Kirindy Forest are up to 26 km² (10 sq mi) large, compared to 13 km² (5 sq mi) for females. These ranges overlap—by about 30% according to data from the eastern forests—but females usually have separated ranges. Home ranges grow during the dry season, perhaps because less food and water is available. In general, radio-collared
fossas travel between 2 and 5 km (1.2 and 3.1 mi) per day, although in one reported case a fossa was observed moving a straight-line distance of 7 km (4.3 mi) in 16 hours. The animal's population density appears to be low: in Kirindy Forest, where it is thought to be common, its density has been estimated at one animal per 4 km² (1.5 sq mi) in 1998. Another study in the same forest between 1994 and 1996 using the mark and recapture
method indicated a population density of one animal per 3.8 km² (1.5 sq mi) and one adult per 5.6 km² (2.2 sq mi).
Except for mothers with young and occasional observations of pairs of males, animals are usually found alone, so that the species is considered solitary. A 2009 publication, however, reported a detailed observation of cooperative hunting, wherein three male fossas hunted a 3 kilogram sifaka (Propithecus verreauxi) for 45 minutes, and subsequently shared the prey. This behavior may be a vestige of cooperative hunting that would have been required to take down larger recently extinct lemurs
.
Fossas communicate using sounds, scents, and visual signals. Vocalizations include purring, a threatening call, and a call of fear, consisting of "repeated loud, coarse inhalations and gasps of breath". A long, high yelp may function to attract other fossas. Females mew during mating and males produce a sigh when they have found a female. Throughout the year, animals produce long-lasting scent marks on rocks, trees, and the ground using glands in the anal region and on the chest. They also communicate using face and body expression, but the significance of these signals is uncertain. The animal is aggressive only during mating, and males in particular fight boldly. After a short fight, the loser flees and is followed by the winner for a short distance. In captivity, fossas are usually not aggressive and sometimes even allow themselves to be stroked by a zookeeper, but adult males in particular may try to bite.
that hunts small to medium-sized animals. One of eight carnivorous species endemic to Madagascar, the fossa is the island's largest surviving endemic terrestrial mammal and the only predator capable of preying upon adults of all extant lemur species, the largest of which can weigh as much as 90% of the weight of the average fossa. Although it is the predominant predator of lemurs, reports of its dietary habits demonstrate a wide variety of prey selectivity and specialization depending on habitat and season; diet does not vary by sex. While the fossa is thought to be a lemur specialist in Ranomafana National Park
, its diet is more variable in other rain forest habitats.
The diet of the fossa in the wild has been studied by analyzing their distinctive scats
, which resemble gray cylinders with twisted ends and measure 10 – long by 1.5 – thick. Scat collected and analyzed from both Andohahela and Andringitra contained lemur matter and rodents. Eastern populations in Andringitra incorporate the widest recorded variety of prey, including both vertebrates and invertebrate
s. Vertebrates consumed ranged from reptile
s to a wide variety of birds, including both understory
and ground birds, and mammals, including insectivore
s, rodent
s, and lemurs. Invertebrates eaten by the fossa in the high mountain zone of Andringitra include insects and crabs. One study found that vertebrates comprised 94% of the diet of fossas, with lemurs comprising over 50%, followed by tenrecs (9%), lizards (9%), and birds (2%). Seeds, which comprised 5% of the diet, may have been in the stomachs of the lemurs eaten, or may have been consumed with fruit taken for water, as seeds were more common in the stomach in the dry season. The average prey size varies geographically; it is only 40 grams (1.4 oz) in the high mountains of Andringitra, in contrast to 480 grams (16.9 oz) in humid forests and over 1000 grams (35.3 oz) in dry deciduous forests. In a study of fossa diet in the dry deciduous forest of western Madagascar, more than 90% of prey items were vertebrates, and more than 50% were lemurs. The primary diet consisted of approximately six lemur species and two or three spiny tenrec species, along with snakes and small mammals. Generally, the fossa preys upon larger lemurs and rodents in preference to smaller ones.
Prey is obtained by hunting either on the ground or in the trees. During the non-breeding season the fossa hunts individually, but during the breeding season hunting parties may be seen, and these may be pairs or later on mothers and young. One member of the group scales a tree and chases the lemurs from tree to tree, forcing them down to the ground where the other is easily able to capture them. The fossa is known to eviscerate its larger lemur prey, a trait that, along with its distinct scat, helps identify its kills. Long-term observations of the fossa's predation patterns on rainforest sifaka
s suggest that the fossa hunts in a subsection of their range until prey density is decreased, then moves on. The fossa has been reported to prey on domestic animals, such as goats and small calves, and especially chickens. In captivity, the fossa consumes between 800 and 1000 g (28.2 and 35.3 oz) of meat a day. Food taken in captivity includes amphibians, birds, insects, reptiles, and small- to medium-sized mammals.
This wide variety of prey items taken in various rainforest habitats is similar to the varied dietary composition noted occurring in the dry forests of western Madagascar, as well. As the largest endemic predator on Madagascar, this dietary flexibility combined with a flexible activity pattern has allowed it to exploit a wide variety of niches available throughout the island, making it a potential keystone species
for the Madagascar ecosystems.
Most of the details of reproduction in wild populations are from the western dry deciduous forests; whether certain of these details are applicable to eastern populations will require further field research. Mating typically occurs during September and October, although there are reports of it occurring as late as December, and can be highly conspicuous. In captivity in the Northern Hemisphere
, fossas instead mate in the northern Spring, from March to July. Intromission usually occurs in trees on horizontal limbs about 20 m (65.6 ft) off the ground. Frequently the same tree is used year after year, with remarkable precision as to the date the season commences. Trees are often near a water source, and have limbs strong enough and wide enough to support the mating pair, about 20 cm (7.9 in) wide. Some mating has been reported on the ground as well.
As many as eight males will be at a mating site, staying in close vicinity to the receptive female. The female seems to choose the male she mates with, and the males compete for the attention of the female with a significant amount of vocalization
and antagonistic interactions. The female may choose to mate with several of the males, and her choice of mate does not seem to have any correlation to the physical appearance of the males. To stimulate the male to mount her, she gives a series of mewling vocalizations. The male mounts from behind, resting his body on her slightly off-center, a position requiring delicate balance; if the female were to stand, the male would have significant difficulty continuing. He places his paws on her shoulders or grasps her around the waist and often licks her neck. Mating may last for nearly three hours. This unusually lengthy mating is due to the physical nature of the male's erect penis, which has backwards-pointing spine
s along most of its length. Fossa mating includes a copulatory tie, which may be enforced by the male's spiny penis. The tie is difficult to break if the mating session is interrupted. Copulation with a single male may be repeated several times, with a total mating time of up to fourteen hours, while the male may remain with the female for up to an hour after the mating. A single female may occupy the tree for up to a week, mating with multiple males over that time. Also, other females may take her place, mating with some of the same males as well as others. This mating strategy, whereby the females monopolize a site and maximize the available number of mates, seems to be unique among carnivores. Recent research suggests that this system helps the fossa overcome factors which would normally impede mate-finding, such as low population density and lack of den use.
The birthing of the litter of one to six (typically two to four) takes place in a concealed location, such as an underground den, a termite mound, a rock crevice, or in the hollow of a large tree (particularly those of the Commiphora
genus). Contrary to older research, litters are of mixed sexes. Young are born in December or January, making the gestation period
90 days, with the late mating reports indicating a gestational period of about six to seven weeks. The newborns are blind and toothless, and weigh no more than 100 g (3.5 oz). The fur is thin and has been described as gray-brown or nearly white. After about two weeks the cubs' eyes open, they become more active, and their fur darkens to a pearl gray. The cubs do not take solid food until three months old, and do not leave the den until they are 4.5 months old; they are weaned shortly after that. After the first year, the juveniles are independent of their mother. Permanent teeth appear at 18 to 20 months. Physical maturity is reached by about two years old, but sexual maturity
is not attained for another year or two, and the young may stay with their mother until they are fully mature. Lifespan in captivity is up to or past 20 years of age, possibly due to the slow juvenile development.
" by the IUCN Red List
since 2008, as its population size has probably declined by at least 30% over the last 21 years; previous assessments have included "Endangered
" (2000) and "Insufficiently Known" (1988, 1990, 1994). The species is dependent on forest and thus threatened by the widespread destruction of Madagascar's native forest, but is also able to persist in disturbed areas. A suite of microsatellite markers (short segments of DNA that have a repeated sequence
) have been developed to help aid in studies of genetic health and population dynamics
of both captive and wild fossas. Several pathogen
s have been isolated from the fossa, some of which, such as anthrax
and canine distemper
, are thought to have been transmitted by feral dogs or cats.
Although the species is widely distributed, it is locally rare in all regions, making them particularly vulnerable to extinction. The effects of habitat fragmentation
increase the risk. For its size, the fossa has a lower than predicted population density, which is further threatened by Madagascar's rapidly disappearing forests and dwindling lemur populations, which make up a high proportion of its diet. The loss of the fossa, either locally or completely, could significantly impact ecosystem dynamics, possibly leading to over-grazing by some of its prey species. The total population of the fossa living within protected areas is estimated at less than 2,500 adults, but this may be an overestimate. Only two protected areas are thought to contain 500 or more adult fossas: Masoala National Park
and Midongy-Sud National Park
, although these are also thought to be overestimated. Too little population information has been collected for a formal population viability analysis
, but estimates suggest that none of the protected areas support a viable population
. If this is correct, the extinction of the fossa may take as much as 100 years to occur as the species gradually declines. In order for the species to survive, it is estimated that at least 555 km² (214.3 sq mi) is needed to maintain smaller, short-term viable populations, and at least 2000 km² (772.2 sq mi) for populations of 500 adults.
Taboo
, known in Madagascar as fady, offers protection for the fossa and other carnivores. In the Marolambo District (part of the Atsinanana
region in Toamasina Province
), the fossa has traditionally been hated and feared as a dangerous animal. It has been described as "greedy and aggressive", known for taking fowl and piglets, and believed to "take little children who walk alone into the forest". Some do not eat it for fear that it will transfer its undesirable qualities to anyone who consumes it. However, the animal is also taken for bushmeat
; a study published in 2009 reported that 57% of villages (8 of 14 sampled) in the Makira forest consume fossa meat. The animals were typically hunted using slingshots, with dogs, or most commonly, by placing snare traps on animal paths. Near Ranomafana National Park
, the fossa, along with several of its smaller cousins and the introduced small Indian civet
(Viverricula indica), are known to "scavenge on the bodies of ancestors", which are buried in shallow graves in the forest. For this reason, eating these animals is strictly prohibited by fady. However, if they wander into villages in search of domestic fowl, they may be killed or trapped. Small carnivore traps have been observed near chicken runs in the village of Vohiparara.
Fossas are occasionally held in captivity in zoo
s. They first bred in captivity in 1974 in the zoo of Montpellier
, France. The next year, at a time when there were only eight fossas in the world's zoos, the Duisburg Zoo
in Germany acquired one; this zoo later started a successful breeding program, and most zoo fossas now descend from the Duisburg population. Research on the Duisburg fossas has provided much data about their biology.
Cat
The cat , also known as the domestic cat or housecat to distinguish it from other felids and felines, is a small, usually furry, domesticated, carnivorous mammal that is valued by humans for its companionship and for its ability to hunt vermin and household pests...
-like, carnivorous mammal
Mammal
Mammals are members of a class of air-breathing vertebrate animals characterised by the possession of endothermy, hair, three middle ear bones, and mammary glands functional in mothers with young...
that is endemic to Madagascar
Madagascar
The Republic of Madagascar is an island country located in the Indian Ocean off the southeastern coast of Africa...
. It is a member of the Eupleridae
Eupleridae
The family Eupleridae is a group of carnivorans endemic to Madagascar and comprising 10 known species in seven genera. Probably the best known species is the Fossa , in the subfamily Euplerinae...
, a family
Family (biology)
In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...
of carnivora
Carnivora
The diverse order Carnivora |Latin]] carō "flesh", + vorāre "to devour") includes over 260 species of placental mammals. Its members are formally referred to as carnivorans, while the word "carnivore" can refer to any meat-eating animal...
ns closely related to the mongoose
Mongoose
Mongoose are a family of 33 living species of small carnivorans from southern Eurasia and mainland Africa. Four additional species from Madagascar in the subfamily Galidiinae, which were previously classified in this family, are also referred to as "mongooses" or "mongoose-like"...
family (Herpestidae). Its classification
Biological classification
Biological classification, or scientific classification in biology, is a method to group and categorize organisms by biological type, such as genus or species. Biological classification is part of scientific taxonomy....
has been controversial because its physical traits resemble those of cats
Felidae
Felidae is the biological family of the cats; a member of this family is called a felid. Felids are the strictest carnivores of the thirteen terrestrial families in the order Carnivora, although the three families of marine mammals comprising the superfamily pinnipedia are as carnivorous as the...
, yet other traits suggest a close relationship with viverrids (most civets and their relatives). Its classification, along with that of the other Malagasy carnivores, influenced hypotheses about how many times mammalian carnivores have colonized the island. With genetic studies demonstrating that the fossa and all other Malagasy carnivores are most closely related to each other (forming a clade
Cladistics
Cladistics is a method of classifying species of organisms into groups called clades, which consist of an ancestor organism and all its descendants . For example, birds, dinosaurs, crocodiles, and all descendants of their most recent common ancestor form a clade...
, recognized as the family Eupleridae), carnivorans are now thought to have colonized the island once around 18 to 20 million years ago.
The fossa is the largest mammalian carnivore
Carnivore
A carnivore meaning 'meat eater' is an organism that derives its energy and nutrient requirements from a diet consisting mainly or exclusively of animal tissue, whether through predation or scavenging...
on the island of Madagascar and has been compared to a small cougar. Adults have a head-body length of 70–80 cm (27.6–31.5 in) and weigh between 5.5 kilogram, with the males larger than the females. It has semi-retractable claws and flexible ankles that allow it to climb up and down trees head-first, and also support jumping from tree to tree. The fossa is unique within its family for the shape of its genitalia, which share traits with those of cats and hyena
Hyena
Hyenas or Hyaenas are the animals of the family Hyaenidae of suborder feliforms of the Carnivora. It is the fourth smallest biological family in the Carnivora , and one of the smallest in the mammalia...
s.
The species is widespread, although population densities
Population density
Population density is a measurement of population per unit area or unit volume. It is frequently applied to living organisms, and particularly to humans...
are usually low. It is found solely in forested habitat, and actively hunts both by day and night. Over 50% of its diet consists of lemur
Lemur
Lemurs are a clade of strepsirrhine primates endemic to the island of Madagascar. They are named after the lemures of Roman mythology due to the ghostly vocalizations, reflective eyes, and the nocturnal habits of some species...
s, the endemic primate
Primate
A primate is a mammal of the order Primates , which contains prosimians and simians. Primates arose from ancestors that lived in the trees of tropical forests; many primate characteristics represent adaptations to life in this challenging three-dimensional environment...
s found on the island; tenrecs, rodent
Rodent
Rodentia is an order of mammals also known as rodents, characterised by two continuously growing incisors in the upper and lower jaws which must be kept short by gnawing....
s, lizards, birds, and other animals are also documented as prey. Mating usually occurs in trees on horizontal limbs and can last for several hours. Litters range from one to six pups, which are born blind and toothless (altricial
Altricial
Altricial, meaning "requiring nourishment", refers to a pattern of growth and development in organisms which are incapable of moving around on their own soon after hatching or being born...
). Infants wean after 4.5 months and are independent after a year. Sexual maturity
Sexual maturity
Sexual maturity is the age or stage when an organism can reproduce. It is sometimes considered synonymous with adulthood, though the two are distinct...
occurs around three to four years of age, and life expectancy in captivity is 20 years. The fossa is listed as "Vulnerable
Vulnerable species
On 30 January 2010, the IUCN Red List of Threatened Species identified 9694 Vulnerable species, subspecies and varieties, stocks and sub-populations.-References:...
" by the International Union for Conservation of Nature (IUCN). It is generally feared by the Malagasy people and is often protected by their taboo
Taboo
A taboo is a strong social prohibition relating to any area of human activity or social custom that is sacred and or forbidden based on moral judgment, religious beliefs and or scientific consensus. Breaking the taboo is usually considered objectionable or abhorrent by society...
, known as fady. The greatest threat to the species is habitat destruction
Habitat destruction
Habitat destruction is the process in which natural habitat is rendered functionally unable to support the species present. In this process, the organisms that previously used the site are displaced or destroyed, reducing biodiversity. Habitat destruction by human activity mainly for the purpose of...
.
Etymology
The genus name Cryptoprocta refers to how the animal's anusAnus
The anus is an opening at the opposite end of an animal's digestive tract from the mouth. Its function is to control the expulsion of feces, unwanted semi-solid matter produced during digestion, which, depending on the type of animal, may be one or more of: matter which the animal cannot digest,...
is hidden by its anal pouch, from the Ancient Greek
Ancient Greek
Ancient Greek is the stage of the Greek language in the periods spanning the times c. 9th–6th centuries BC, , c. 5th–4th centuries BC , and the c. 3rd century BC – 6th century AD of ancient Greece and the ancient world; being predated in the 2nd millennium BC by Mycenaean Greek...
words crypto- "hidden", and procta "anus". The species name ferox is the Latin
Latin
Latin is an Italic language originally spoken in Latium and Ancient Rome. It, along with most European languages, is a descendant of the ancient Proto-Indo-European language. Although it is considered a dead language, a number of scholars and members of the Christian clergy speak it fluently, and...
adjective "fierce" or "wild." Its common name
Common name
A common name of a taxon or organism is a name in general use within a community; it is often contrasted with the scientific name for the same organism...
is spelled fossa in English or fosa in Malagasy
Malagasy language
Malagasy is the national language of Madagascar, a member of the Austronesian family of languages. Most people in Madagascar speak it as a first language as do some people of Malagasy descent elsewhere.-History:...
, the Austronesian language
Austronesian languages
The Austronesian languages are a language family widely dispersed throughout the islands of Southeast Asia and the Pacific, with a few members spoken on continental Asia that are spoken by about 386 million people. It is on par with Indo-European, Niger-Congo, Afroasiatic and Uralic as one of the...
from which was taken. The word is similar to posa (meaning "cat
Cat
The cat , also known as the domestic cat or housecat to distinguish it from other felids and felines, is a small, usually furry, domesticated, carnivorous mammal that is valued by humans for its companionship and for its ability to hunt vermin and household pests...
") in the Iban language
Iban language
The Iban language is spoken by the Iban, a branch of the Dayak ethnic group formerly known as "Sea Dayak" who live in Sarawak, the Indonesian province of Kalimantan Barat and in Brunei. It belongs to the Malayo-Polynesian branch of the Austronesian language family, and is related to Malay, more...
(another Austronesian language) from Borneo
Borneo
Borneo is the third largest island in the world and is located north of Java Island, Indonesia, at the geographic centre of Maritime Southeast Asia....
, and both terms may derived from trade languages from 1600s. However, an alternative etymology
Etymology
Etymology is the study of the history of words, their origins, and how their form and meaning have changed over time.For languages with a long written history, etymologists make use of texts in these languages and texts about the languages to gather knowledge about how words were used during...
suggests a link to another word that comes from Malay
Malay language
Malay is a major language of the Austronesian family. It is the official language of Malaysia , Indonesia , Brunei and Singapore...
: pusa refers to the Malayan weasel
Malayan Weasel
The Malayan weasel is a species of weasel. It lives in Brunei, Indonesia, Malaysia, and Thailand. It is rated "Least Concern" by the IUCN Red List. Malayan weasels have a body length of 12-14 inches and a tail length of 9.4 to 10.2 inches. The body is reddish-brown to grayish-white. The head is a...
(Mustela nudipes). The Malay word pusa could have become posa for cats in Borneo while in Madagascar the word could have become fosa to refer to the fossa.
Taxonomy
The fossa was formally described in 1833 by Edward Turner BennettEdward Turner Bennett
Edward Turner Bennett was an English zoologist and writer. He was the elder brother of the botanist John Joseph Bennett. Bennett was born at Hackney and practiced as a surgeon, but his chief pursuit was always zoology...
. The common name is the same as the generic name of the Malagasy civet (Fossa fossana), but they are different species. Because of shared physical traits with civet
Civet
The family Viverridae is made up of around 30 species of medium-sized mammal, including all of the genets, the binturong, most of the civets, and the two African linsangs....
s, mongoose
Mongoose
Mongoose are a family of 33 living species of small carnivorans from southern Eurasia and mainland Africa. Four additional species from Madagascar in the subfamily Galidiinae, which were previously classified in this family, are also referred to as "mongooses" or "mongoose-like"...
s, and cats (Felidae
Felidae
Felidae is the biological family of the cats; a member of this family is called a felid. Felids are the strictest carnivores of the thirteen terrestrial families in the order Carnivora, although the three families of marine mammals comprising the superfamily pinnipedia are as carnivorous as the...
), its classification
Biological classification
Biological classification, or scientific classification in biology, is a method to group and categorize organisms by biological type, such as genus or species. Biological classification is part of scientific taxonomy....
has been controversial. Bennett originally placed the fossa as a type of civet
Civet
The family Viverridae is made up of around 30 species of medium-sized mammal, including all of the genets, the binturong, most of the civets, and the two African linsangs....
in the family Viverridae, a classification that long remained popular among taxonomists. Its compact braincase, large eye sockets
Orbit (anatomy)
In anatomy, the orbit is the cavity or socket of the skull in which the eye and its appendages are situated. "Orbit" can refer to the bony socket, or it can also be used to imply the contents...
, retractable claws, and specialized carnivorous dentition
Dentition
Dentition pertains to the development of teeth and their arrangement in the mouth. In particular, the characteristic arrangement, kind, and number of teeth in a given species at a given age...
have also led some taxonomists to associate it with the felids. In 1939, William King Gregory
William King Gregory
William King Gregory was an American zoologist, renowned as a primatologist, paleontologist, and functional and comparative morphologist. He was an expert on mammalian dentition, and a leading contributor to theories of evolution...
and Milo Hellman placed the fossa in its own subfamily within Felidae, the Cryptoproctinae. George Gaylord Simpson
George Gaylord Simpson
George Gaylord Simpson was an American paleontologist. Simpson was perhaps the most influential paleontologist of the twentieth century, and a major participant in the modern evolutionary synthesis, contributing Tempo and mode in evolution , The meaning of evolution and The major features of...
placed it back in Viverridae in 1945, still within its own subfamily, yet conceded it had many cat-like characteristics.
In 1993, Géraldine Veron and François Catzeflis published a DNA hybridization study suggesting that the fossa was more closely related to mongooses (family Herpestidae) than to cats or civets. However, in 1995, Veron's morphological
Morphology (biology)
In biology, morphology is a branch of bioscience dealing with the study of the form and structure of organisms and their specific structural features....
study once again grouped it with Felidae. In 2003, molecular phylogenetic studies using nuclear
Nuclear DNA
Nuclear DNA, nuclear deoxyribonucleic acid , is DNA contained within a nucleus of eukaryotic organisms. In mammals and vertebrates, nuclear DNA encodes more of the genome than the mitochondrial DNA and is composed of information inherited from two parents, one male, and one female, rather than...
and mitochondrial genes
Mitochondrial DNA
Mitochondrial DNA is the DNA located in organelles called mitochondria, structures within eukaryotic cells that convert the chemical energy from food into a form that cells can use, adenosine triphosphate...
by Anne Yoder and colleagues showed that all native Malagasy carnivorans share a common ancestry that excludes other carnivores (meaning they form a clade
Cladistics
Cladistics is a method of classifying species of organisms into groups called clades, which consist of an ancestor organism and all its descendants . For example, birds, dinosaurs, crocodiles, and all descendants of their most recent common ancestor form a clade...
, making them monophyletic
Monophyly
In common cladistic usage, a monophyletic group is a taxon which forms a clade, meaning that it contains all the descendants of the possibly hypothetical closest common ancestor of the members of the group. The term is synonymous with the uncommon term holophyly...
) and are most closely related to Asian and African Herpestidae. To reflect these relationships, all Malagasy carnivorans are now placed in a single family, Eupleridae
Eupleridae
The family Eupleridae is a group of carnivorans endemic to Madagascar and comprising 10 known species in seven genera. Probably the best known species is the Fossa , in the subfamily Euplerinae...
. Within Eupleridae, the fossa is placed in the subfamily Euplerinae
Euplerinae
Euplerinae is a subfamily of carnivorans that includes three species restricted to Madagascar. Together with the subfamily Galidiinae, which also occurs on Madagascar only, it forms the family Eupleridae...
with the falanouc
Falanouc
The Falanouc is a rare mongoose-like mammal endemic Malagasy euplerid .It is classified alongside its closest living relative, the Fanaloka, in the subfamily Euplerinae. The Falanouc has several peculiarities which merit its independent classification...
(Eupleres goudoti) and Malagasy Civet, but its exact relationships are poorly resolved.
An extinct relative of the fossa was described in 1902 from subfossil
Subfossil
Subfossil refers to remains whose fossilization process is not complete, either for lack of time or because the conditions in which they were buried were not optimal for fossilization....
remains and recognized as a separate species, Cryptoprocta spelea
Cryptoprocta spelea
Cryptoprocta spelea, also known as the giant fossa, is an extinct species of carnivore from Madagascar in the family Eupleridae, which is most closely related to the mongooses and includes all Malagasy carnivorans. It was first described in 1902, and in 1935 was recognized as a separate species...
, in 1935. This species was larger than the living fossa (with a body mass estimate roughly twice as great), but otherwise similar. Across Madagascar, people distinguish two kinds of fossa—a large fosa mainty ("black fossa") and the smaller fosa mena ("reddish fossa")—and a white form has been reported in the southwest. It is unclear whether this is purely folklore or individual variation—related to sex, age or instances of melanism
Melanism
Melanism is an undue development of dark-colored pigment in the skin or its appendages, and the opposite of albinism. It is also the medical term for black jaundice.The word is deduced from the , meaning black pigment....
and leucism—or whether there is indeed more than one species of living fossa.
Description
The fossa appears as a diminutive form of a large felid, such as a cougar, but with a slender body and muscular limbs, and a tail nearly as long as the rest of the body. It has a mongooseMongoose
Mongoose are a family of 33 living species of small carnivorans from southern Eurasia and mainland Africa. Four additional species from Madagascar in the subfamily Galidiinae, which were previously classified in this family, are also referred to as "mongooses" or "mongoose-like"...
-like head, relatively longer than that of a cat, although with a muzzle that is broad and short, and with large but rounded ears. It has medium brown eyes set relatively wide apart with pupils that contract to slits. Like many carnivorans that hunt at night, its eyes reflect light
Tapetum lucidum
The tapetum lucidum is a layer of tissue in the eye of many vertebrate animals....
; the reflected light is orange in hue.
Its head-body length is 70–80 cm (27.6–31.5 in) and its tail is 65–70 cm (25.6–27.6 in) long. There is some sexual dimorphism
Sexual dimorphism
Sexual dimorphism is a phenotypic difference between males and females of the same species. Examples of such differences include differences in morphology, ornamentation, and behavior.-Examples:-Ornamentation / coloration:...
, with adult males (weighing 6.2–8.6 kg; 14–19 lb) being larger than females (5.5–6.8 kg; 12–15 lb). Smaller individuals are typically found north and east on Madagascar, while larger ones to the south and west. Unusually large individuals weighing up to 20 kg (44.1 lb) have been reported, but there is some doubt as to the reliability of the measurements. The fossa can smell, hear, and see well. It is a robust animal and illnesses are rare in captive fossas.
Both males and females have short, straight fur that is relatively dense and without spots or patterns. Both sexes are generally a reddish-brown dorsally and colored a dirty cream ventrally. When in rut, they may have an orange coloration to their abdomen
Abdomen
In vertebrates such as mammals the abdomen constitutes the part of the body between the thorax and pelvis. The region enclosed by the abdomen is termed the abdominal cavity...
from a reddish substance secreted by a chest gland
Gland
A gland is an organ in an animal's body that synthesizes a substance for release of substances such as hormones or breast milk, often into the bloodstream or into cavities inside the body or its outer surface .- Types :...
secretions, but this has not been consistently observed by all researchers. The tail tends to be lighter in coloration than the sides. Juveniles are either gray or nearly white.
Several of the animal's physical features are adaptions to climbing through trees. It uses its tail to aid in balance and has semi-retractable claws that it uses to climb trees in its search for prey. It has semiplantigrade
Plantigrade
right|151px|thumb|Human skeleton, showing plantigrade habitIn terrestrial animals, plantigrade locomotion means walking with the podials and metatarsals flat on the ground. It is one of three forms of locomotion adopted by mammals...
feet, switching between a plantigrade-like gait (when arboreal) and a digitigrade
Digitigrade
A digitigrade is an animal that stands or walks on its digits, or toes. Digitigrades include walking birds , cats, dogs, and many other mammals, but not plantigrades or unguligrades...
-like one (when terrestrial
Terrestrial animal
Terrestrial animals are animals that live predominantly or entirely on land , as compared with aquatic animals, which live predominantly or entirely in the water , or amphibians, which rely on a combination of aquatic and terrestrial habitats...
). The soles of its paws are nearly bare and covered with strong pads. The fossa has very flexible ankles that allow it to readily grasp tree trunks so as to climb up or down trees head first or to leap to another tree. Captive juveniles have been known to swing upside down by their hindfeet from knotted ropes.
The fossa has several scent gland
Scent gland
Scent glands are found in the genital area of most mammals and in various other parts of the body, such as the underarms of humans and the preorbital glands of deer and muskox. They produce a semi-viscous fluid which contains pheromones. These odor-messengers indicate information such as status,...
s, although the glands are less developed in females. Like herpestids it has a perianal skin gland inside an anal sac which surrounds the anus like a pocket. The pocket opens to the exterior with a horizontal slit below the tail. Other glands are located near the penis or vagina, with the penile glands emitting a strong odor. Like the herpestids, it has no prescrotal glands.
One of the more interesting physical features of this species is its external genitalia. Males have an unusually long penis and baculum
Baculum
The baculum is a bone found in the penis of most mammals. It is absent in humans, but present in other primates, such as the gorilla and chimpanzee.The bone aids in sexual intercourse.-Purpose:...
(penis bone), reaching to between its forelegs when erect. The glans
Glans
The glans is a vascular structure located at the tip of the penis in men or a homologous genital structure of the clitoris in women.-Structure:...
extends about halfway down the shaft and is spiny except at the tip. In comparison, the glans of felids is short and spiny, while that of viverrids is smooth and long. The female fossa exhibits transient masculization, starting at about 1–2 years of age, developing an enlarged, spiny clitoris
Clitoris
The clitoris is a sexual organ that is present only in female mammals. In humans, the visible button-like portion is located near the anterior junction of the labia minora, above the opening of the urethra and vagina. Unlike the penis, which is homologous to the clitoris, the clitoris does not...
that resembles a male's penis. The enlarged clitoris is supported by an os clitoridis, which decreases in size as the animal grows. Females do not have a pseudo-scrotum, but they do secrete an orange substance that colors their underparts, much like the secretions of males. Hormone levels (testosterone
Testosterone
Testosterone is a steroid hormone from the androgen group and is found in mammals, reptiles, birds, and other vertebrates. In mammals, testosterone is primarily secreted in the testes of males and the ovaries of females, although small amounts are also secreted by the adrenal glands...
, androstenedione
Androstenedione
Androstenedione is a 19-carbon steroid hormone produced in the adrenal glands and the gonads as an intermediate step in the biochemical pathway that produces the androgen testosterone and the estrogens estrone and estradiol.-Synthesis:Androstenedione is the common precursor of male and female sex...
, dihydrotestosterone
Dihydrotestosterone
Dihydrotestosterone is an androgen or male sex hormone. The enzyme 5α-reductase synthesises DHT in the prostate, testes, hair follicles, and adrenal glands...
) do not seem to play a part in this transient masculization, as those levels are the same in masculinized juveniles and nonmasculinized adults. It is speculated that the transient masculization either reduces sexual harassment of juvenile females by adult males, or reduces aggression from territorial females. While females of other mammal species (such as the spotted hyena
Spotted Hyena
The spotted hyena also known as laughing hyena, is a carnivorous mammal of the family Hyaenidae, of which it is the largest extant member. Though the species' prehistoric range included Eurasia extending from Atlantic Europe to China, it now only occurs in all of Africa south of the Sahara save...
) have a pseudo-penis
Pseudo-penis
A pseudo-penis is a term used of any structure found on an animal that while superficially appearing to be a penis, is derived from a different developmental path.-Mammals:...
, none of them are known to have theirs diminish in size as the animal grows.
Comparison with related carnivores
Overall, the fossa has features in common with three different carnivoran families, leading researchers to place it and other members of Eupleridae alternatively in Herpestidae, Viverridae, and Felidae. Felid features are primarily those associated with eating and digestionDigestion
Digestion is the mechanical and chemical breakdown of food into smaller components that are more easily absorbed into a blood stream, for instance. Digestion is a form of catabolism: a breakdown of large food molecules to smaller ones....
, including teeth shape and facial
Facial
A facial is a procedure involving a variety of skin treatments, including: steam, exfoliation, extraction, creams, lotions, facial masks, peels, and massage...
portions of the skull, the tongue, and the digestive tract, typical of its exclusively carnivorous diet. The remainder of the skull most closely resembles those of genus Viverra
Viverra
Viverra is a genus of civet commonly found in Southeast Asia.-Species:* Malabar Large-spotted Civet * Large-spotted Civet * Malayan Civet * Large Indian Civet...
, while the general body structure is most similar to that of various members of Herpestidae. The permanent dentition is (three incisor
Incisor
Incisors are the first kind of tooth in heterodont mammals. They are located in the premaxilla above and mandible below.-Function:...
s, one canine
Canine tooth
In mammalian oral anatomy, the canine teeth, also called cuspids, dogteeth, fangs, or eye teeth, are relatively long, pointed teeth...
, three or four premolar
Premolar
The premolar teeth or bicuspids are transitional teeth located between the canine and molar teeth. In humans, there are two premolars per quadrant, making eight premolars total in the mouth. They have at least two cusps. Premolars can be considered as a 'transitional tooth' during chewing, or...
s, and one molar
Molar (tooth)
Molars are the rearmost and most complicated kind of tooth in most mammals. In many mammals they grind food; hence the Latin name mola, "millstone"....
on each side of both the upper and lower jaws), with the deciduous formula being similar but lacking the fourth premolar and the molar. The fossa has a large, prominent rhinarium
Rhinarium
The rhinarium is the moist, naked surface around the nostrils of the nose in most mammals. In actual scientific usage it is typically called a "wet snout" or "wet nose" from its moist and shiny appearance...
similar to that of viverrids, but has comparatively larger, round ears, almost as large as those of a similarly sized felid. Its facial vibrissae
Vibrissae
Vibrissae , or whiskers, are specialized hairs usually employed for tactile sensation. The term may also refer to the thick hairs found inside human nostrils, but these have no sensorial function and only operate as an airborne particulate barrier...
(whiskers) are long, with the longest being longer than its head. Like some mongoose genera, particularly Galidia (which is now in the fossa's own family, Eupleridae) and Herpestes
Herpestes
Herpestes is a genus of the mongoose family, Herpestidae .It contains the following species and subspecies:* Short-tailed Mongoose, Herpestes brachyurus** H. b. brachyurus...
(of Herpestidae), it has carpal vibrassae as well. Its claws are retractile, but unlike those of Felidae species, they are not hidden in skin sheaths. It has three pairs of nipples (one inguinal, one ventral, and one pectoral).
Habitat and distribution
The fossa has the most widespread geographical range of the Malagasy carnivores, and is generally found in low numbers throughout the island in remaining tracts of forest, preferring pristine undisturbed forest habitat. It is also encountered in some degraded forests, but in lower numbers. Although the fossa is found in all known forest habitats throughout Madagascar, including the western, dry deciduous forests, the eastern rainforestRainforest
Rainforests are forests characterized by high rainfall, with definitions based on a minimum normal annual rainfall of 1750-2000 mm...
s, and the southern spiny forests
Madagascar spiny thickets
The Madagascar spiny thickets is an ecoregion in Madagascar. The vegetation type is found on poor substrates with low, erratic winter rainfall. An estimated 14,000 to is covered with this habitat, all in the southwest of the country...
, it is seen more frequently in humid than in dry forests. This may be because the reduced canopy in dry forests provides less shade, and also because the fossa seems to travel more easily in humid forests. It is absent from areas with the heaviest habitat disturbance and, like most of Madagascar's fauna, from the central high plateau of the country.
The fossa has been found across several different elevational gradients in undisturbed portions of protected areas throughout Madagascar. In the Réserve Naturelle Intégrale d'Andringitra, evidence of the fossa has been reported at four different sites ranging from 810 to 1625 m (2,657.5 to 5,331.4 ft). Its highest known occurrence was reported at 2000 m (6,561.7 ft); its presence high on the Andringitra Massif
Andringitra Massif
The Andringitra Massif is a granite massif located within Andringitra National Park in Madagascar. Pic Boby, the highest peak, is at 2658 meters high. Today, it is mainly occupied by herders and shepherds who are constantly moving in order to find the freshest grazing grounds for their livestock...
was subsequently confirmed in 1996. Similarly, evidence has been reported of the fossa at the elevational extremes of 440 m (1,443.6 ft) and 1875 m (6,151.6 ft) in the Andohahela National Park
Andohahela National Park
Andohahela National Park, in southeast Madagascar, is remarkable for the extremes of habitats that are representened within it. The park covers 760 square kilometers of the Anosy mountain range, the southernmost spur of the Malagasy Highlands...
. The presence of the fossa at these locations indicates its ability to adapt to various elevations, consistent with its reported distribution in all Madagascar forest types.
Behavior
Cathemeral
A cathemeral organism is one that has sporadic and random intervals of activity during the day or night in which food is acquired, socializing with other organisms occurs, and any other activities necessary for livelihood are performed...
; activity peaks may occur early in the morning, late in the afternoon, and late in the night. The animal generally does not reuse sleeping sites, but females with young do return to the same den. The home ranges of male fossas in Kirindy Forest are up to 26 km² (10 sq mi) large, compared to 13 km² (5 sq mi) for females. These ranges overlap—by about 30% according to data from the eastern forests—but females usually have separated ranges. Home ranges grow during the dry season, perhaps because less food and water is available. In general, radio-collared
Tracking collar
Tracking collars are collars used as a radio beacon to track animal migration for research. Some pet owners use these collars for GPS tracking and geofencing of their pets....
fossas travel between 2 and 5 km (1.2 and 3.1 mi) per day, although in one reported case a fossa was observed moving a straight-line distance of 7 km (4.3 mi) in 16 hours. The animal's population density appears to be low: in Kirindy Forest, where it is thought to be common, its density has been estimated at one animal per 4 km² (1.5 sq mi) in 1998. Another study in the same forest between 1994 and 1996 using the mark and recapture
Mark and recapture
Mark and recapture is a method commonly used in ecology to estimate population size. This method is most valuable when a researcher fails to detect all individuals present within a population of interest every time that researcher visits the study area...
method indicated a population density of one animal per 3.8 km² (1.5 sq mi) and one adult per 5.6 km² (2.2 sq mi).
Except for mothers with young and occasional observations of pairs of males, animals are usually found alone, so that the species is considered solitary. A 2009 publication, however, reported a detailed observation of cooperative hunting, wherein three male fossas hunted a 3 kilogram sifaka (Propithecus verreauxi) for 45 minutes, and subsequently shared the prey. This behavior may be a vestige of cooperative hunting that would have been required to take down larger recently extinct lemurs
Subfossil lemur
Subfossil lemurs are lemurs from Madagascar that are represented by recent remains dating from nearly 26,000 years ago to approximately 560 years ago. They include both living and extinct species, although the term more frequently refers to the extinct giant lemurs...
.
Fossas communicate using sounds, scents, and visual signals. Vocalizations include purring, a threatening call, and a call of fear, consisting of "repeated loud, coarse inhalations and gasps of breath". A long, high yelp may function to attract other fossas. Females mew during mating and males produce a sigh when they have found a female. Throughout the year, animals produce long-lasting scent marks on rocks, trees, and the ground using glands in the anal region and on the chest. They also communicate using face and body expression, but the significance of these signals is uncertain. The animal is aggressive only during mating, and males in particular fight boldly. After a short fight, the loser flees and is followed by the winner for a short distance. In captivity, fossas are usually not aggressive and sometimes even allow themselves to be stroked by a zookeeper, but adult males in particular may try to bite.
Diet
The fossa is a carnivoreCarnivore
A carnivore meaning 'meat eater' is an organism that derives its energy and nutrient requirements from a diet consisting mainly or exclusively of animal tissue, whether through predation or scavenging...
that hunts small to medium-sized animals. One of eight carnivorous species endemic to Madagascar, the fossa is the island's largest surviving endemic terrestrial mammal and the only predator capable of preying upon adults of all extant lemur species, the largest of which can weigh as much as 90% of the weight of the average fossa. Although it is the predominant predator of lemurs, reports of its dietary habits demonstrate a wide variety of prey selectivity and specialization depending on habitat and season; diet does not vary by sex. While the fossa is thought to be a lemur specialist in Ranomafana National Park
Ranomafana National Park
Ranomafana National Park is located in the southeastern part of Madagascar in Haute Matsiatra and Vatovavy-Fitovinany. With more than 41,600 hectares of moist forest climate, the park is home to several rare species of flora and fauna such as the lemur...
, its diet is more variable in other rain forest habitats.
The diet of the fossa in the wild has been studied by analyzing their distinctive scats
Feces
Feces, faeces, or fæces is a waste product from an animal's digestive tract expelled through the anus or cloaca during defecation.-Etymology:...
, which resemble gray cylinders with twisted ends and measure 10 – long by 1.5 – thick. Scat collected and analyzed from both Andohahela and Andringitra contained lemur matter and rodents. Eastern populations in Andringitra incorporate the widest recorded variety of prey, including both vertebrates and invertebrate
Invertebrate
An invertebrate is an animal without a backbone. The group includes 97% of all animal species – all animals except those in the chordate subphylum Vertebrata .Invertebrates form a paraphyletic group...
s. Vertebrates consumed ranged from reptile
Reptile
Reptiles are members of a class of air-breathing, ectothermic vertebrates which are characterized by laying shelled eggs , and having skin covered in scales and/or scutes. They are tetrapods, either having four limbs or being descended from four-limbed ancestors...
s to a wide variety of birds, including both understory
Understory
Understory is the term for the area of a forest which grows at the lowest height level below the forest canopy. Plants in the understory consist of a mixture of seedlings and saplings of canopy trees together with understory shrubs and herbs...
and ground birds, and mammals, including insectivore
Insectivore
An insectivore is a type of carnivore with a diet that consists chiefly of insects and similar small creatures. An alternate term is entomophage, which also refers to the human practice of eating insects....
s, rodent
Rodent
Rodentia is an order of mammals also known as rodents, characterised by two continuously growing incisors in the upper and lower jaws which must be kept short by gnawing....
s, and lemurs. Invertebrates eaten by the fossa in the high mountain zone of Andringitra include insects and crabs. One study found that vertebrates comprised 94% of the diet of fossas, with lemurs comprising over 50%, followed by tenrecs (9%), lizards (9%), and birds (2%). Seeds, which comprised 5% of the diet, may have been in the stomachs of the lemurs eaten, or may have been consumed with fruit taken for water, as seeds were more common in the stomach in the dry season. The average prey size varies geographically; it is only 40 grams (1.4 oz) in the high mountains of Andringitra, in contrast to 480 grams (16.9 oz) in humid forests and over 1000 grams (35.3 oz) in dry deciduous forests. In a study of fossa diet in the dry deciduous forest of western Madagascar, more than 90% of prey items were vertebrates, and more than 50% were lemurs. The primary diet consisted of approximately six lemur species and two or three spiny tenrec species, along with snakes and small mammals. Generally, the fossa preys upon larger lemurs and rodents in preference to smaller ones.
Prey is obtained by hunting either on the ground or in the trees. During the non-breeding season the fossa hunts individually, but during the breeding season hunting parties may be seen, and these may be pairs or later on mothers and young. One member of the group scales a tree and chases the lemurs from tree to tree, forcing them down to the ground where the other is easily able to capture them. The fossa is known to eviscerate its larger lemur prey, a trait that, along with its distinct scat, helps identify its kills. Long-term observations of the fossa's predation patterns on rainforest sifaka
Sifaka
Sifakas are a genus of lemur from the family Indriidae within the order Primates. Their name of the family is an onomatopoeia of their characteristic "shi-fak" alarm call. Like all lemurs, they are found only on the island of Madagascar...
s suggest that the fossa hunts in a subsection of their range until prey density is decreased, then moves on. The fossa has been reported to prey on domestic animals, such as goats and small calves, and especially chickens. In captivity, the fossa consumes between 800 and 1000 g (28.2 and 35.3 oz) of meat a day. Food taken in captivity includes amphibians, birds, insects, reptiles, and small- to medium-sized mammals.
This wide variety of prey items taken in various rainforest habitats is similar to the varied dietary composition noted occurring in the dry forests of western Madagascar, as well. As the largest endemic predator on Madagascar, this dietary flexibility combined with a flexible activity pattern has allowed it to exploit a wide variety of niches available throughout the island, making it a potential keystone species
Keystone species
A keystone species is a species that has a disproportionately large effect on its environment relative to its abundance. Such species play a critical role in maintaining the structure of an ecological community, affecting many other organisms in an ecosystem and helping to determine the types and...
for the Madagascar ecosystems.
Breeding
Northern Hemisphere
The Northern Hemisphere is the half of a planet that is north of its equator—the word hemisphere literally means “half sphere”. It is also that half of the celestial sphere north of the celestial equator...
, fossas instead mate in the northern Spring, from March to July. Intromission usually occurs in trees on horizontal limbs about 20 m (65.6 ft) off the ground. Frequently the same tree is used year after year, with remarkable precision as to the date the season commences. Trees are often near a water source, and have limbs strong enough and wide enough to support the mating pair, about 20 cm (7.9 in) wide. Some mating has been reported on the ground as well.
As many as eight males will be at a mating site, staying in close vicinity to the receptive female. The female seems to choose the male she mates with, and the males compete for the attention of the female with a significant amount of vocalization
Animal communication
Animal communication is any behavior on the part of one animal that has an effect on the current or future behaviour of another animal. The study of animal communication, is sometimes called Zoosemiotics has played an important part in the...
and antagonistic interactions. The female may choose to mate with several of the males, and her choice of mate does not seem to have any correlation to the physical appearance of the males. To stimulate the male to mount her, she gives a series of mewling vocalizations. The male mounts from behind, resting his body on her slightly off-center, a position requiring delicate balance; if the female were to stand, the male would have significant difficulty continuing. He places his paws on her shoulders or grasps her around the waist and often licks her neck. Mating may last for nearly three hours. This unusually lengthy mating is due to the physical nature of the male's erect penis, which has backwards-pointing spine
Spine (zoology)
A spine is a hard, thorny or needle-like structure which occurs on various animals. Animals such as porcupines and sea urchins grow spines as a self-defense mechanism. Spines are often formed of keratin...
s along most of its length. Fossa mating includes a copulatory tie, which may be enforced by the male's spiny penis. The tie is difficult to break if the mating session is interrupted. Copulation with a single male may be repeated several times, with a total mating time of up to fourteen hours, while the male may remain with the female for up to an hour after the mating. A single female may occupy the tree for up to a week, mating with multiple males over that time. Also, other females may take her place, mating with some of the same males as well as others. This mating strategy, whereby the females monopolize a site and maximize the available number of mates, seems to be unique among carnivores. Recent research suggests that this system helps the fossa overcome factors which would normally impede mate-finding, such as low population density and lack of den use.
The birthing of the litter of one to six (typically two to four) takes place in a concealed location, such as an underground den, a termite mound, a rock crevice, or in the hollow of a large tree (particularly those of the Commiphora
Commiphora
Commiphora is a genus of flowering plants in the family Burseraceae. It includes about 185 species of trees and shrubs, often armed or thorny, native to Africa, Arabia, and the Indian subcontinent.-Uses:...
genus). Contrary to older research, litters are of mixed sexes. Young are born in December or January, making the gestation period
Gestation period
For mammals the gestation period is the time in which a fetus develops, beginning with fertilization and ending at birth. The duration of this period varies between species.-Duration:...
90 days, with the late mating reports indicating a gestational period of about six to seven weeks. The newborns are blind and toothless, and weigh no more than 100 g (3.5 oz). The fur is thin and has been described as gray-brown or nearly white. After about two weeks the cubs' eyes open, they become more active, and their fur darkens to a pearl gray. The cubs do not take solid food until three months old, and do not leave the den until they are 4.5 months old; they are weaned shortly after that. After the first year, the juveniles are independent of their mother. Permanent teeth appear at 18 to 20 months. Physical maturity is reached by about two years old, but sexual maturity
Sexual maturity
Sexual maturity is the age or stage when an organism can reproduce. It is sometimes considered synonymous with adulthood, though the two are distinct...
is not attained for another year or two, and the young may stay with their mother until they are fully mature. Lifespan in captivity is up to or past 20 years of age, possibly due to the slow juvenile development.
Human interactions
The fossa has been assessed as "VulnerableVulnerable species
On 30 January 2010, the IUCN Red List of Threatened Species identified 9694 Vulnerable species, subspecies and varieties, stocks and sub-populations.-References:...
" by the IUCN Red List
IUCN Red List
The IUCN Red List of Threatened Species , founded in 1963, is the world's most comprehensive inventory of the global conservation status of biological species. The International Union for Conservation of Nature is the world's main authority on the conservation status of species...
since 2008, as its population size has probably declined by at least 30% over the last 21 years; previous assessments have included "Endangered
Endangered species
An endangered species is a population of organisms which is at risk of becoming extinct because it is either few in numbers, or threatened by changing environmental or predation parameters...
" (2000) and "Insufficiently Known" (1988, 1990, 1994). The species is dependent on forest and thus threatened by the widespread destruction of Madagascar's native forest, but is also able to persist in disturbed areas. A suite of microsatellite markers (short segments of DNA that have a repeated sequence
DNA sequence
The sequence or primary structure of a nucleic acid is the composition of atoms that make up the nucleic acid and the chemical bonds that bond those atoms. Because nucleic acids, such as DNA and RNA, are unbranched polymers, this specification is equivalent to specifying the sequence of...
) have been developed to help aid in studies of genetic health and population dynamics
Population dynamics
Population dynamics is the branch of life sciences that studies short-term and long-term changes in the size and age composition of populations, and the biological and environmental processes influencing those changes...
of both captive and wild fossas. Several pathogen
Pathogen
A pathogen gignomai "I give birth to") or infectious agent — colloquially, a germ — is a microbe or microorganism such as a virus, bacterium, prion, or fungus that causes disease in its animal or plant host...
s have been isolated from the fossa, some of which, such as anthrax
Anthrax
Anthrax is an acute disease caused by the bacterium Bacillus anthracis. Most forms of the disease are lethal, and it affects both humans and other animals...
and canine distemper
Canine distemper
Canine distemper is a viral disease that affects animals in the families Canidae, Mustelidae, Mephitidae, Hyaenidae, Ailuridae, Procyonidae, Pinnipedia, some Viverridae and Felidae...
, are thought to have been transmitted by feral dogs or cats.
Although the species is widely distributed, it is locally rare in all regions, making them particularly vulnerable to extinction. The effects of habitat fragmentation
Habitat fragmentation
Habitat fragmentation as the name implies, describes the emergence of discontinuities in an organism's preferred environment , causing population fragmentation...
increase the risk. For its size, the fossa has a lower than predicted population density, which is further threatened by Madagascar's rapidly disappearing forests and dwindling lemur populations, which make up a high proportion of its diet. The loss of the fossa, either locally or completely, could significantly impact ecosystem dynamics, possibly leading to over-grazing by some of its prey species. The total population of the fossa living within protected areas is estimated at less than 2,500 adults, but this may be an overestimate. Only two protected areas are thought to contain 500 or more adult fossas: Masoala National Park
Masoala National Park
Masoala National Park, in northeast Madagascar, is the largest of the island's protected areas. Most of the park is situated in Sava Region and a part in Analanjirofo. Created in 1997, the park protects 2,300 square kilometres of rainforest and 100 square kilometres of marine parks. The Masoala...
and Midongy-Sud National Park
Midongy du sud National Park
Midongy du sud National Park is a national park of Madagascar....
, although these are also thought to be overestimated. Too little population information has been collected for a formal population viability analysis
Population viability analysis
Population viability analysis is a species-specific method of risk assessment frequently used in conservation biology.It is traditionally defined as the process that determines the probability that a population will go extinct within a given number of years.More recently, PVA has been described...
, but estimates suggest that none of the protected areas support a viable population
Small population size
Small populations behave differently from larger populations. They often result in population bottlenecks, which have harmful consequences for the survival of that population.-Demographic effects:...
. If this is correct, the extinction of the fossa may take as much as 100 years to occur as the species gradually declines. In order for the species to survive, it is estimated that at least 555 km² (214.3 sq mi) is needed to maintain smaller, short-term viable populations, and at least 2000 km² (772.2 sq mi) for populations of 500 adults.
Taboo
Taboo
A taboo is a strong social prohibition relating to any area of human activity or social custom that is sacred and or forbidden based on moral judgment, religious beliefs and or scientific consensus. Breaking the taboo is usually considered objectionable or abhorrent by society...
, known in Madagascar as fady, offers protection for the fossa and other carnivores. In the Marolambo District (part of the Atsinanana
Atsinanana
Atsinanana is a region in eastern Madagascar. It borders Analanjirofo region in north, Alaotra-Mangoro in west, Vakinankaratra and Amoron'i Mania in southwest and Vatovavy-Fitovinany in south.Atsinanana region is divided into seven districts:...
region in Toamasina Province
Toamasina Province
Toamasina is a former province of Madagascar with an area of 71,911 km². It had a population of 2,855,600 . Its capital was Toamasina, the most important seaport of the country....
), the fossa has traditionally been hated and feared as a dangerous animal. It has been described as "greedy and aggressive", known for taking fowl and piglets, and believed to "take little children who walk alone into the forest". Some do not eat it for fear that it will transfer its undesirable qualities to anyone who consumes it. However, the animal is also taken for bushmeat
Bushmeat
Bushmeat initially referred to the hunting of wild animals in West and Central Africa and is a calque from the French viande de brousse. Today the term is commonly used for meat of terrestrial wild animals, killed for subsistence or commercial purposes throughout the humid tropics of the Americas,...
; a study published in 2009 reported that 57% of villages (8 of 14 sampled) in the Makira forest consume fossa meat. The animals were typically hunted using slingshots, with dogs, or most commonly, by placing snare traps on animal paths. Near Ranomafana National Park
Ranomafana National Park
Ranomafana National Park is located in the southeastern part of Madagascar in Haute Matsiatra and Vatovavy-Fitovinany. With more than 41,600 hectares of moist forest climate, the park is home to several rare species of flora and fauna such as the lemur...
, the fossa, along with several of its smaller cousins and the introduced small Indian civet
Small Indian Civet
The Small Indian Civet or Rasse is a species of civet found across south and South-east Asia as well as in the Indonesian archipelago. The Assamese name Johamaal refers to its glandular odour similar to a scented rice variety called Joha...
(Viverricula indica), are known to "scavenge on the bodies of ancestors", which are buried in shallow graves in the forest. For this reason, eating these animals is strictly prohibited by fady. However, if they wander into villages in search of domestic fowl, they may be killed or trapped. Small carnivore traps have been observed near chicken runs in the village of Vohiparara.
Fossas are occasionally held in captivity in zoo
Zoo
A zoological garden, zoological park, menagerie, or zoo is a facility in which animals are confined within enclosures, displayed to the public, and in which they may also be bred....
s. They first bred in captivity in 1974 in the zoo of Montpellier
Montpellier
-Neighbourhoods:Since 2001, Montpellier has been divided into seven official neighbourhoods, themselves divided into sub-neighbourhoods. Each of them possesses a neighbourhood council....
, France. The next year, at a time when there were only eight fossas in the world's zoos, the Duisburg Zoo
Duisburg Zoo
The Duisburg Zoo, founded on May 12, 1934, is one of the largest zoological gardens in Germany. It is especially well known for its dolphinarium and, since 1994, for breeding koalas....
in Germany acquired one; this zoo later started a successful breeding program, and most zoo fossas now descend from the Duisburg population. Research on the Duisburg fossas has provided much data about their biology.
External links
- ARKive – images and movies of the Fossa (Cryptoprocta ferox)
- Watch more fossa (Cryptoprocta ferox) video clips from the BBC archive on Wildlife Finder