Horsfield's Tarsier
Encyclopedia
Horsfield's tarsier also known as the western tarsier, is a species of tarsier
. It occurs on Borneo
, Sumatra
and nearby islands.
and the various tarsiers of Sulawesi
and nearby islands; therefore, scientists have proposed to place it in a separate genus, Cephalopachus.
The taxonomy of this species is in doubt, with some subspecies considered unsure. In fact, over 20 years few studies have been done on T. bancanus and a taxonomic revision based upon intensive and systematic field surveys is overdue. The IUCN believes that these subspecies should be treated as distinct and named as separate taxa until more definitive evidence is available.
There are three recognized subspecies of Horfield's tarsier:
claws on each foot. The fingers are very long and have pads on the tips. The toes have flattened nails except for the second and third toes on hind feet, which bear claw-like nails. It has large eyes which do not reflect light. The membranous ears are slender and almost bare. The molar
s of this species have high-cusps and are almost tritubercular. The dental formula of T. bancanus is 2:1:3:3 on the upper jaw and 1:1:3:3 on the lower jaw.
, Borneo
and nearby islands. The Bornean subspecies, T. b. borneanus, is known from many lowland sites in Sabah
, Brunei
, Sarawak
and West Kalimantan
and above 900m in the Kelabit uplands in Northern Sarawak
. Other records show it from Kutai and Peleben in East Kalimantan
and Tanjung Maruwe in Central Kalimantan
.
This species is a carnivorous species. It mainly eats insects such as beetle
s, grasshopper
s, cockroach
es, butterflies, moth
s, praying mantis, ant
s, phasmids
, and cicada
s, but also will eat small vertebrates such as bats (Chiroptera) including members of the Taphozous
genus, the Lesser Short-nosed Fruit Bat (Cynopterus brachyotis), and the Spotted-winged Fruit Bat (Balionycteris maculata
), and snakes, of which poisonous snakes have been found to be consumed. For example, the poisonous snake Manticora intestinalis was found to be hunted for by this species. This species was also found to consume bird
s, including: spider-hunters, warbler
s, kingfisher
s, and pitta
s. It locates prey primarily by sound and catches the prey with its hands when foraging. The prey items get killed by bites to the back of the neck and the eyes are shut when attacking. It will consume the prey starting with the head and working its way down the body. This species gets water both by drinking from a pool or steam, and by licking drops from bamboo leaves or from trunks of trees when water is running down the bark.
T. bancanus, like all tarsiers, is a vertical clinger and leaper known for its extraordinary leaping abilities. An individual will mainly support itself with its feet and the tail exerts enough force to hold the individual in place without using the hands much because of the pads located on the feet. Except when resting, the hands are usually placed no higher than ots nose. The hands are only placed higher up to maintain the position of the individual. Other modes of locomotion of this species are climbing, quadrupedal, walking, hopping and "cantilevering."
Horsfield's tarsier is monogamous, with acopulation frequency during estrus of once per night. Courtship
call
s are performed by the male and he emits 2-3 chirrups while opening and closing the mouth. This call happens within 5 minutes of looking at the female. Once the male gives his courtship call, if the female is receptive, she will perform genital displays to him. If the female is not in estrus, she will emit an agonistic call which is often followed by biting and pushing the male away. Both of each call lasts on average for 1 second and the interval between each call is on average 3 seconds.
Infants are born with their eyes open and fully furred and are able to groom themselves. The mother will carry her infant in her mouth and when she forages for food the mother will park the infant on a branch. Infant sounds are mostly clicks: "k", "tk", "ki", or a rapid "kooih" and can be heard when the infant is left alone or is cold. The mother stays in contact with their infants using high-pitched calls. Infants were found to first use the tails as support during resting at 7–10 days. Young leave their range at the onset of puberty, and find their own territory.
Social grooming in this species only occurs between mothers and infants, removing dead skin and parasites by scratching with their toe claws and licking their fur, avoiding their faces. Faces are cleaned by rubbing on branches and it is to reinforce social bonds.
Horsfield's tarsier marks its territory with scents from urine and glandular secretions on a substrate while scratching the surface with its hindlimb toe claws.
Horsfield's tarsier is listed as vulnerable
in the 2008 IUCN Red List of Threatened Species, listed in CITES Appendix II, and protected by law in Indonesia and in Malaysia.
In February 2007, the governments of Brunei
, Malaysia, and Indonesia
agreed to protect roughly 220000 km² (84,942.5 sq mi) of tropical forest in the "Heart of Borneo
" region. Environmental group WWF
was particularly active in the establishment of the protected area. In the "Heart of Borneo" project, non-governmental organization
s (NGOs) have played role in promoting the critical initiative and in assisting the transboundary nations in its conceptualization, design, and implementation. The transboundary nations are to improve biodiversity conservation in Bornean production forests, and to ensure that such forests are not simply converted to agricultural land-uses such as oil-palm plantations after logging.
Tarsier
Tarsiers are haplorrhine primates of the genus Tarsius, a genus in the family Tarsiidae, which is itself the lone extant family within the infraorder Tarsiiformes...
. It occurs on 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....
, Sumatra
Sumatra
Sumatra is an island in western Indonesia, westernmost of the Sunda Islands. It is the largest island entirely in Indonesia , and the sixth largest island in the world at 473,481 km2 with a population of 50,365,538...
and nearby islands.
Taxonomic notes
Although Horsfield's tarsier is usually placed in the genus Tarsius with all other living tarsiers, it is quite distinct from the Philippine tarsierPhilippine Tarsier
The Philippine Tarsier , known locally as the Kupal in Cebuano/Visayan and Mamag in Luzon, is an endangered species of tarsier endemic to the Philippines. It is found in the southeastern part of the archipelago, particularly in the islands of Bohol, Samar, Leyte and Mindanao...
and the various tarsiers of Sulawesi
Sulawesi
Sulawesi is one of the four larger Sunda Islands of Indonesia and is situated between Borneo and the Maluku Islands. In Indonesia, only Sumatra, Borneo, and Papua are larger in territory, and only Java and Sumatra have larger Indonesian populations.- Etymology :The Portuguese were the first to...
and nearby islands; therefore, scientists have proposed to place it in a separate genus, Cephalopachus.
The taxonomy of this species is in doubt, with some subspecies considered unsure. In fact, over 20 years few studies have been done on T. bancanus and a taxonomic revision based upon intensive and systematic field surveys is overdue. The IUCN believes that these subspecies should be treated as distinct and named as separate taxa until more definitive evidence is available.
- Tarsius bancanus bancanus
- Belitung Island tarsier, Tarsius bancanus saltator
- Bornean tarsier, Tarsius bancanus borneanus
Morphology
The pelage coloration range from pale-olive or reddish brown to pale or dark grey-brown, possibly varying with age. Based on 12 collected specimens, the range measurement from head to body is 121-154 mm. T. bancanus has an extremely long tail which can reach 181 to 224 mm and is hairless except for tufts of hair at the end. This species has two groomingPersonal grooming
Personal grooming is the art of cleaning, grooming, and maintaining parts of the body. It is a species-typical behavior that is controlled by neural circuits in the brain.- In humans :...
claws on each foot. The fingers are very long and have pads on the tips. The toes have flattened nails except for the second and third toes on hind feet, which bear claw-like nails. It has large eyes which do not reflect light. The membranous ears are slender and almost bare. The 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"....
s of this species have high-cusps and are almost tritubercular. The dental formula of T. bancanus is 2:1:3:3 on the upper jaw and 1:1:3:3 on the lower jaw.
Distributions
T. bancanus is found in Southern SumatraSumatra
Sumatra is an island in western Indonesia, westernmost of the Sunda Islands. It is the largest island entirely in Indonesia , and the sixth largest island in the world at 473,481 km2 with a population of 50,365,538...
, 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 nearby islands. The Bornean subspecies, T. b. borneanus, is known from many lowland sites in Sabah
Sabah
Sabah is one of 13 member states of Malaysia. It is located on the northern portion of the island of Borneo. It is the second largest state in the country after Sarawak, which it borders on its southwest. It also shares a border with the province of East Kalimantan of Indonesia in the south...
, Brunei
Brunei
Brunei , officially the State of Brunei Darussalam or the Nation of Brunei, the Abode of Peace , is a sovereign state located on the north coast of the island of Borneo, in Southeast Asia...
, Sarawak
Sarawak
Sarawak is one of two Malaysian states on the island of Borneo. Known as Bumi Kenyalang , Sarawak is situated on the north-west of the island. It is the largest state in Malaysia followed by Sabah, the second largest state located to the North- East.The administrative capital is Kuching, which...
and West Kalimantan
Kalimantan
In English, the term Kalimantan refers to the Indonesian portion of the island of Borneo, while in Indonesian, the term "Kalimantan" refers to the whole island of Borneo....
and above 900m in the Kelabit uplands in Northern Sarawak
Sarawak
Sarawak is one of two Malaysian states on the island of Borneo. Known as Bumi Kenyalang , Sarawak is situated on the north-west of the island. It is the largest state in Malaysia followed by Sabah, the second largest state located to the North- East.The administrative capital is Kuching, which...
. Other records show it from Kutai and Peleben in East Kalimantan
Kalimantan
In English, the term Kalimantan refers to the Indonesian portion of the island of Borneo, while in Indonesian, the term "Kalimantan" refers to the whole island of Borneo....
and Tanjung Maruwe in Central Kalimantan
Kalimantan
In English, the term Kalimantan refers to the Indonesian portion of the island of Borneo, while in Indonesian, the term "Kalimantan" refers to the whole island of Borneo....
.
Ecology
Horsfield's tarsier is a nocturnal species. It sleeps alone during the day in a tangle of vines or creepers at a height of 3.5 to 5 meters. This species prefers to sleep, rest, or remain stationary on perches that are angled 5 degrees from the vertical tree trunks, 1 to 4 cm in diameter, and it sleeps solitarily. Before sunset, T. bancanus will wake up and wait 10 to 20 minutes before moving around the understory and spending 1.5 to 2 hours of the night foraging for food. Horsfield's Tarsier can be found from ground level up to at least 7m in the understory.This species is a carnivorous species. It mainly eats insects such as beetle
Beetle
Coleoptera is an order of insects commonly called beetles. The word "coleoptera" is from the Greek , koleos, "sheath"; and , pteron, "wing", thus "sheathed wing". Coleoptera contains more species than any other order, constituting almost 25% of all known life-forms...
s, grasshopper
Grasshopper
The grasshopper is an insect of the suborder Caelifera in the order Orthoptera. To distinguish it from bush crickets or katydids, it is sometimes referred to as the short-horned grasshopper...
s, cockroach
Cockroach
Cockroaches are insects of the order Blattaria or Blattodea, of which about 30 species out of 4,500 total are associated with human habitations...
es, butterflies, moth
Moth
A moth is an insect closely related to the butterfly, both being of the order Lepidoptera. Moths form the majority of this order; there are thought to be 150,000 to 250,000 different species of moth , with thousands of species yet to be described...
s, praying mantis, ant
Ant
Ants are social insects of the family Formicidae and, along with the related wasps and bees, belong to the order Hymenoptera. Ants evolved from wasp-like ancestors in the mid-Cretaceous period between 110 and 130 million years ago and diversified after the rise of flowering plants. More than...
s, phasmids
Phasmatodea
The Phasmatodea are an order of insects, whose members are variously known as stick insects , walking sticks or stick-bugs , phasmids, ghost insects and leaf insects...
, and cicada
Cicada
A cicada is an insect of the order Hemiptera, suborder Auchenorrhyncha , in the superfamily Cicadoidea, with large eyes wide apart on the head and usually transparent, well-veined wings. There are about 2,500 species of cicada around the world, and many of them remain unclassified...
s, but also will eat small vertebrates such as bats (Chiroptera) including members of the Taphozous
Taphozous
Taphozous is a genus of sac-winged bat in the family Emballonuridae.It contains the following species:* Indonesian Tomb Bat * Coastal Tomb Bat * Sharp-Nosed Tomb Bat...
genus, the Lesser Short-nosed Fruit Bat (Cynopterus brachyotis), and the Spotted-winged Fruit Bat (Balionycteris maculata
Balionycteris maculata
The Spotted-winged Fruit Bat, Balionycteris maculata is the smallest megabat in the world. It is in the monotypic genus Balionycteris. It is found from southern Thailand, across Malaysia, and on the island of Borneo. It lives in the forests where it roosts in small groups in trees and caves...
), and snakes, of which poisonous snakes have been found to be consumed. For example, the poisonous snake Manticora intestinalis was found to be hunted for by this species. This species was also found to consume bird
Bird
Birds are feathered, winged, bipedal, endothermic , egg-laying, vertebrate animals. Around 10,000 living species and 188 families makes them the most speciose class of tetrapod vertebrates. They inhabit ecosystems across the globe, from the Arctic to the Antarctic. Extant birds range in size from...
s, including: spider-hunters, warbler
Warbler
There are a number of Passeriformes called "warblers". They are not particularly closely related, but share some characteristics, such as being fairly small, vocal and insectivorous....
s, kingfisher
Kingfisher
Kingfishers are a group of small to medium sized brightly coloured birds in the order Coraciiformes. They have a cosmopolitan distribution, with most species being found in the Old World and Australia...
s, and pitta
Pitta
Pitta may stand for:*Pittas, a family of tropical birds*Pitta bread *Pitta , an island in the Dodecanese archipelago, in the Aegean Sea...
s. It locates prey primarily by sound and catches the prey with its hands when foraging. The prey items get killed by bites to the back of the neck and the eyes are shut when attacking. It will consume the prey starting with the head and working its way down the body. This species gets water both by drinking from a pool or steam, and by licking drops from bamboo leaves or from trunks of trees when water is running down the bark.
T. bancanus, like all tarsiers, is a vertical clinger and leaper known for its extraordinary leaping abilities. An individual will mainly support itself with its feet and the tail exerts enough force to hold the individual in place without using the hands much because of the pads located on the feet. Except when resting, the hands are usually placed no higher than ots nose. The hands are only placed higher up to maintain the position of the individual. Other modes of locomotion of this species are climbing, quadrupedal, walking, hopping and "cantilevering."
Horsfield's tarsier is monogamous, with acopulation frequency during estrus of once per night. Courtship
Courtship
Courtship is the period in a couple's relationship which precedes their engagement and marriage, or establishment of an agreed relationship of a more enduring kind. In courtship, a couple get to know each other and decide if there will be an engagement or other such agreement...
call
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...
s are performed by the male and he emits 2-3 chirrups while opening and closing the mouth. This call happens within 5 minutes of looking at the female. Once the male gives his courtship call, if the female is receptive, she will perform genital displays to him. If the female is not in estrus, she will emit an agonistic call which is often followed by biting and pushing the male away. Both of each call lasts on average for 1 second and the interval between each call is on average 3 seconds.
Infants are born with their eyes open and fully furred and are able to groom themselves. The mother will carry her infant in her mouth and when she forages for food the mother will park the infant on a branch. Infant sounds are mostly clicks: "k", "tk", "ki", or a rapid "kooih" and can be heard when the infant is left alone or is cold. The mother stays in contact with their infants using high-pitched calls. Infants were found to first use the tails as support during resting at 7–10 days. Young leave their range at the onset of puberty, and find their own territory.
Social grooming in this species only occurs between mothers and infants, removing dead skin and parasites by scratching with their toe claws and licking their fur, avoiding their faces. Faces are cleaned by rubbing on branches and it is to reinforce social bonds.
Horsfield's tarsier marks its territory with scents from urine and glandular secretions on a substrate while scratching the surface with its hindlimb toe claws.
Habitat
This species can live in both primary and secondary forests, and it also lives in forests along the coasts or on the edge of plantations.Conservation status
The rapid loss of habitat due to forest conversion, oil palm plantations, fire and logging is cause for concern. Additionally, the species is also collected for the illegal pet trade and wrongly considered a pest to agricultural crops. It can suffer, directly and indirectly, from the use of agricultural pesticides.Horsfield's tarsier 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:...
in the 2008 IUCN Red List of Threatened Species, listed in CITES Appendix II, and protected by law in Indonesia and in Malaysia.
In February 2007, the governments of Brunei
Brunei
Brunei , officially the State of Brunei Darussalam or the Nation of Brunei, the Abode of Peace , is a sovereign state located on the north coast of the island of Borneo, in Southeast Asia...
, Malaysia, and Indonesia
Indonesia
Indonesia , officially the Republic of Indonesia , is a country in Southeast Asia and Oceania. Indonesia is an archipelago comprising approximately 13,000 islands. It has 33 provinces with over 238 million people, and is the world's fourth most populous country. Indonesia is a republic, with an...
agreed to protect roughly 220000 km² (84,942.5 sq mi) of tropical forest in the "Heart of Borneo
Heart of Borneo
The Heart of Borneo is a conservation agreement initiated by the World Wide Fund for Nature to protect a 220,000 km² forested region on Borneo island. The agreement has been signed by the governments of Brunei, Indonesia and Malaysia in Bali on 12 February 2007 to support the initiative...
" region. Environmental group WWF
World Wide Fund for Nature
The World Wide Fund for Nature is an international non-governmental organization working on issues regarding the conservation, research and restoration of the environment, formerly named the World Wildlife Fund, which remains its official name in Canada and the United States...
was particularly active in the establishment of the protected area. In the "Heart of Borneo" project, non-governmental organization
Non-governmental organization
A non-governmental organization is a legally constituted organization created by natural or legal persons that operates independently from any government. The term originated from the United Nations , and is normally used to refer to organizations that do not form part of the government and are...
s (NGOs) have played role in promoting the critical initiative and in assisting the transboundary nations in its conceptualization, design, and implementation. The transboundary nations are to improve biodiversity conservation in Bornean production forests, and to ensure that such forests are not simply converted to agricultural land-uses such as oil-palm plantations after logging.