Tarantula
Encyclopedia
Tarantulas comprise a group of often hairy and often very large arachnid
s belonging to the family
Theraphosidae, of which approximately 900 species have been identified. Some members of the same Suborder may also be called "tarantulas" in the common parlance. This article will restrict itself to describing members of Theraphosidae. They are also called Athropodes.
Some genera
of tarantulas hunt prey primarily in trees; others hunt on or near the ground. All tarantulas can produce silk—while arboreal species will typically reside in a silken "tube tent", terrestrial species will line their burrows with silk to stabilize the burrow wall and facilitate climbing up and down. Tarantulas mainly eat insects and other arthropods, using ambush as their primary method of prey capture. The biggest tarantulas can kill animals as large as lizard
s, mice
, and bird
s.They can be found in the south and west parts of the USA, Central America, and down throughout South America to the southern parts of Chile, Argentina. Tarantulas can also be found throughout Africa, large parts of Asia and all over Australia. In Europe, there are some species in Spain, Portugal, Turkey, Italy, and in Cyprus. Most tarantulas are harmless to humans, and some species are popular in the exotic pet trade. All tarantulas are venomous, but only some species have venom that, while not known to have ever produced human fatalities, can produce extreme discomfort over a period of several days.
Like all arthropod
s, the tarantula is an invertebrate
that relies on an exoskeleton
for muscular support. A tarantula’s body consists of two main parts, the prosoma (cephalothorax) and the opisthosoma
(abdomen). The prosoma and opisthosoma are connected by the pedicle
, or what is often called the pregenital somite. This waist-like connecting piece is actually part of the prosoma and allows the opisthosoma to move in a wide range of motion relative to the prosoma.
The sizes range from as small as a fingernail to as big as a dinner plate. Depending on the species, the body length of tarantulas ranges from 2.5 to 10 cm (0.984251968503937 to 3.9 ), with 8–30 cm (3.1–11.8 ) leg spans. Leg span is determined by measuring from the tip of the back leg to the tip of the front leg on the opposite side. The largest species of tarantula can weigh over 85 grams (3 oz). The largest of all, the Goliath Birdeater
(Theraphosa blondi) from Venezuela and Brazil, has been reported to have a weight of 150 grams (5.3 oz) and a leg-span of up to 30 centimetres (11.8 in), males being the longer and females greater in girth.
T. apophysis (the Pinkfoot Goliath) was described 187 years after the Goliath Birdeater; therefore its characteristics are not as well attested.T. blondi is generally thought to be the heaviest tarantula, and T. apophysis to have the greatest leg span. Two other species, Lasiodora parahybana
(the Brazilian Salmon Birdeater) and L. klugi, rival the size of the two Goliath spiders.
The majority of North American tarantulas are brown. Elsewhere have been found species colored cobalt blue (Haplopelma lividum
), black with white stripes (Aphonopelma seemanni
), yellow leg markings (Eupalaestrus campestratus
), metallic blue legs with vibrant orange abdomen and greenbottle blue (Chromatopelma cyaneopubescens
). Their natural habitats include savanna
, grassland
s such as the pampa
s, rainforest
s, desert
s, scrubland, mountain
s, and cloud forest
s. They are generally classed among the terrestrial types. They are burrowers that live in the ground.
Tarantulas are becoming increasingly popular as pets and are readily available in captivity.
. The spider originally bearing that name is one of the wolf spider
s, Lycosa tarantula
, found in the region surrounding the southern Italian
town of Taranto
. Compared to new-world tarantulas, wolf spiders are not particularly large or hairy.
, whose cure was believed to involve wild dancing of a kind that has come to be identified with the tarantella
. However, modern research has shown that the bite of L. tarantula is generally not dangerous to human beings. There appears to have existed a different species of spider in the fields around Taranto responsible for fairly severe bites. The likely candidate (and the only spider found in the area which is dangerous to man) is the malmignatte or Mediterranean black widow
. This spider, which belongs in the genus Latrodectus
, is a close relative of the black widow
and redback spiders, and has a bite which is medically significant
. However, Lycosa tarantula, being larger and more fearsome-looking, tended to be unjustly credited with any severe bites.
, they were named "tarantulas", causing usage of the term to shift to the tropical spiders. Nevertheless, these spiders belong to the suborder Mygalomorphae
, and are not closely related to wolf spiders.
The name "tarantula" is also mistakenly applied to other large-bodied spiders, including the purseweb spiders or atypical tarantula
s, the funnel-webs (Dipluridae
and Hexathelidae
), and the "dwarf tarantula
s". These spiders are related to tarantulas (all being mygalomorphs), but are classified in different families
. Huntsman spider
s of the family Sparassidae have also been termed "tarantulas" because of their large size. In fact, they are not related, belonging to the suborder Araneomorphae
.
The eight legs, the two chelicerae
with their fangs, and the pedipalp
s are attached to the prosoma. The chelicerae are two double segment appendages that are located just below the eyes and directly forward of the mouth. The chelicerae contain the venom glands that vent through the fangs. The fangs are hollow extensions of the chelicerae that inject venom into prey or animals that the tarantula bites in defense, and they are also used to masticate. These fangs are articulated so that they can extend downward and outward in preparation to bite or can fold back toward the chelicerae as a pocket knife blade folds back into its handle. The chelicerae of a tarantula completely contain the venom glands and the muscles that surround them, and can cause the venom to be forcefully injected into prey.
The pedipalpi are two six-segment appendages connected to the thorax
near the mouth and protruding on either side of both chelicerae. In most species of tarantula, the pedipalpi contain sharp jagged plates used to cut and crush food often called the coxae
or maxillae
. As with other spiders, the terminal portion of the pedipalpi of males function as part of its reproductive system. Male spiders spin a silken platform (sperm web) on the ground onto which they release semen from glands in their opistoma. Then they insert their pedipalps into the semen, absorb the semen into the pedipalps, and later insert the pedipalps (one at a time) into the reproductive organ of the female, which is located in her abdomen. The terminal segments of the pedipalps of male tarantulas are moderately larger in circumference than those of a female tarantula. Male tarantulas have special spinnerets surrounding the genital opening. Silk for the sperm web of the tarantula is exuded from these special spinnerets.
A tarantula has four pairs of legs and two additional pairs of appendages. Each leg has seven segments which, from the prosoma out, are: coxa, trochanter, femur, patella, tibia, tarsus and pretarsus, and claw. Two or three retractable claws are at the end of each leg. These claws are used to grip surfaces for climbing. Also on the end of each leg, surrounding the claws, is a group of hairs. These hairs, called the scopula, help the tarantula to grip better when climbing surfaces like glass. The fifth pair are the pedipalps which aid in feeling, gripping prey, and mating in the case of a mature male. The sixth pair of appendages are the chelicerae and their attached fangs. When walking, a tarantula's first and third leg on one side move at the same time as the second and fourth legs on the other side of his body. The muscles in a tarantula's legs cause the legs to bend at the joints, but to extend a leg, the tarantula increases the pressure of blood entering the leg.
Tarantulas, like almost all other spiders, have their primary spinnerets at the end of the opisthosoma. Unlike the typical spiders that on average have six, tarantulas have two or four spinnerets. Spinnerets are flexible tubelike structures from which the spider exudes its silk. The tip of each spinneret is called the spinning field. Each spinning field is covered by as many as one hundred spinning tubes through which silk is exuded. This silk hardens on contact with the air to become a threadlike substance.
suggests that it is likely that all tarantulas have the ability to produce silk from their tarsi (feet). The existence of these structures is thought to enable the spiders to cling to smooth surfaces and thus avoid a harmful fall. The discovery was published in the Journal of Experimental Biology.
The tarantula's mouth is located under its chelicerae on the lower front part of its prosoma. The mouth is a short straw-shaped opening that can only suck, meaning that anything taken into it must be in liquid form. Prey with large amounts of solid parts, such as mice, must be crushed and ground up or predigested, which is accomplished by coating the prey with digestive juices that are secreted from openings in the chelicerae.
The tarantula's digestive organ (stomach) is a tube that runs the length of its body. In the prosoma, this tube is wider and forms the sucking stomach. When the sucking stomach's powerful muscles contract, the stomach is increased in cross-section, creating a strong sucking action that permits the tarantula to suck its liquefied prey up through the mouth and into the intestines. Once the liquefied food enters the intestines, it is broken down into particles small enough to pass through the intestine walls into the hemolymph
(blood stream) where it is distributed throughout the body. After feeding, the leftovers are formed into a small ball by the tarantula and thrown away. In a terrarium, they often put them into the same corner. As these balls are perfect hosts for mold
s and parasites, they must be removed regularly.
. A tarantula perceives its surroundings primarily via sensory organs called seta
e (hairs or spines). Although a tarantula has eyes, touch is its keenest sense, and in hunting it primarily depends on vibrations given off by the movements of its prey. A tarantula's setae are very sensitive organs and are used to sense chemical signatures, vibrations, wind direction, and possibly even sound. Tarantulas are also very responsive to the presence of certain chemicals such as pheromone
s.
The eyes are located above the chelicerae on the forward part of the prosoma. They are small and usually set in two rows of four. Most tarantulas are not able to see much more than light, darkness, and motion. Arboreal tarantulas generally have better vision compared with terrestrial tarantulas.
s (breathing organs). The first pair of book lungs is located in a cavity inside the lower front part of the abdomen near where the abdomen connects to the cephalothorax and the second pair slightly farther back on the abdomen. Air enters the cavity through a tiny slit on each side of and near the front of the abdomen. Each lung consists of 15 or more thin sheets of folded tissue arranged like the pages of a book. These sheets of tissue are supplied by blood vessels. As air enters each lung, oxygen is taken into the blood stream through the blood vessels in the lungs. Needed moisture may also be absorbed from humid air by these organs.
A tarantula’s blood is unique; an oxygen-transporting protein is present (the copper-based hemocyanin
) but not enclosed in blood cells such as the erythrocytes of mammals. A tarantula’s blood is not true blood but rather a liquid called haemolymph, or hemolymph. There are at least four types of hemocytes, or hemolymph cells. The tarantula’s heart is a long slender tube that is located along the top of the opisthosoma. The heart is neurogenic as opposed to myogenic, so nerve cells instead of muscle cells initiate and coordinate the heart. The heart pumps hemolymph to all parts of the body through open passages often referred to as sinuses, and not through a circular system of blood vessels. If the exoskeleton is breached, loss of hemolymph will kill the tarantula unless the wound is small enough that the hemolymph can dry and close the wound.
s of tarantulas. The largest tarantula hawks, such as those in the genus Pepsis, will track, attack and kill large tarantulas. They use olfaction
to find the lair of a tarantula. The wasp must deliver a sting to the underside of the spider's cephalothorax, exploiting the thin membrane between the basal leg segments. This paralyzes the spider and the wasp then drags it back into its burrow before depositing an egg on the prey's abdomen. The wasp then seals the spider in its burrow and flies off to search for more hosts. The wasp larva hatches and feeds on the spider's non-essential parts and, as it approaches pupation, it consumes the remainder. In addition to more mundane cuisine, tarantulas are considered a delicacy in certain cultures (e.g., Cambodia). They are usually roasted over an open fire to remove the hair and then eaten.
Besides the normal "hairs" covering the body, some tarantulas also have a dense covering of irritating hairs called urticating hair
s, on the opisthosoma, that they sometimes use as protection against enemies. These hairs are present on new-world
species but not on specimens from the Old World
.
Urticating hairs are usually kicked off the abdomen by the tarantula, but it is noteworthy that some may simply rub the abdomen against the target, such is so with the Avicularia
genera. These fine hairs are barbed and serve to irritate. They can be lethal to small animals such as rodents. Some people are extremely sensitive to these hairs, and develop serious itching and rashes at the site. Exposure of the eyes and respiratory system to urticating hairs should be strictly avoided. Species with urticating hairs can kick these hairs off: they are flicked into the air at a target using their back pairs of legs. Tarantulas also use these hairs for other purposes such as to mark territory or to line their shelters (the latter such practice may discourage flies
from feeding on the spiderlings). Urticating hairs do not grow back, but are replaced with each moult
. The intensity, amount, and flotation of the hairs depends on the species of tarantula. Many owners of Goliath Birdeaters (T. blondi) claim that theraphosids have the worst urticating hairs..
To predators and other kinds of enemies, these hairs can range from being lethal to simply being a deterrent. With humans, they can cause irritation to eyes, nose, and skin, and more dangerously, the lungs and airways, if inhaled. The symptoms range from species to species, from person to person, from a burning itch to a minor rash. In some cases, tarantula hairs have caused permanent damage to human eyes.
Some setae are used to stridulate, which makes a hissing sound. These hairs are usually found on the chelicerae. Stridulation
seems to be more common in old-world species.
that is deadly to humans. In general, the effects of the bites of all kinds of tarantula are not well known. While the bites of many species are known to be no worse than a wasp sting, accounts of bites by some species are reported to be very painful and to produce intense spasms that may recur over a period of several days; the venom by the African tarantula Pelinobius muticus also causes strong hallucinations. In all cases, it is prudent to seek medical aid. Because other proteins are included when a toxin
is injected, some individuals may suffer severe symptoms due to an allergic reaction rather than to the venom. Such allergic effects can be life-threatening.
Before biting, tarantulas may signal their intention to attack by rearing up into a "threat posture", which may involve raising their prosoma and lifting their front legs into the air, spreading and extending their fangs, and (in certain species) making a loud hissing by stridulating
. Their next step, short of biting, may be to slap down on the intruder with their raised front legs. If that response fails to deter the attacker, the tarantulas of the Americas may next turn away and flick urticating hairs toward the pursuing predator. The next response may be to leave the scene entirely, but, especially if there is no line of retreat, their final response may also be to whirl suddenly and bite. Some tarantulas are well known to give "dry bites," i.e., they may defensively bite some animal that intrudes on their space and threatens them, but they will not pump venom into the wound.
New-world tarantulas (those found in North
and South America
) are equipped with urticating hair
s on their abdomen, and will almost always throw
these barbed hairs as a first line of defense. These hairs will irritate sensitive areas of the body and especially seem to target curious animals who may sniff these hairs into the mucous membranes of the nose. Some species have more effective urticating hairs than others. The Goliath Birdeater is one species known for its particularly irritating urticating hairs. Urticating hairs can penetrate the cornea
so eye protection should be worn when handling such tarantulas.
Old-world tarantulas (from Europe, Africa, Asia and Australia) have no urticating hairs and are more likely to attack when disturbed. Old-world tarantulas often have more potent, medically significant venom.
There are dangerous spider species which are related to tarantulas and frequently confused with them. A popular urban legend
maintains that deadly varieties of tarantula exist somewhere in South America. This claim is often made without identifying a particular spider, although the "banana tarantula" is sometimes named. A likely candidate for the true identity of this spider is the dangerous Brazilian wandering spider
Phoneutria nigriventer, of the family Ctenidae
, as it is sometimes found hiding in clusters of bananas and is one of several spiders called the "banana spider." It is not technically a tarantula but it is fairly large (4–5 inches long), somewhat hairy, and is highly venomous to humans. Another dangerous type of spider that has been confused with tarantulas is the Australasian funnel-web spider
. The best known of these is the Sydney funnel-web spider Atrax robustus, a spider that is aggressive, highly venomous, and (prior to the development of antivenin
in the 1980s) was responsible for numerous deaths in Australia
. These spiders are members of the same suborder as tarantulas. (Some Australians use the slang term 'triantelope' for large, hairy, and harmless members of the Huntsman spider
family which are often found on interior household walls and in automobiles.)
, sometimes spider bites are regarded as the probable source of infections. Medical advice regarding prophylaxis may be helpful in that regard. In addition, there is considerable anecdotal evidence indicating that the venoms of some old-world species can produce symptoms so severe that medical treatment would be appropriate. Medical intervention is also regarded as appropriate when symptoms such as breathing difficulty or chest pain develop, since these conditions may indicate an anaphylactic
reaction. As with bee sting
s, allergic reactions to protein fractions may be many times more dangerous than the direct toxic effects of the venom.
Urticating hairs may cause medical problems for humans should they enter the eyes or the respiratory system. Unless one inhales air heavily laden with these hairs or rubs them into one's eyes, they are rarely a problem. Some individuals are more sensitive to skin contact with these spines and learn to avoid them when cleaning cages or otherwise coming into potential contact with them.
. Males tend to be smaller (especially their abdomens, which can appear quite narrow) and may be dull in color when compared to their female counterparts, as in the species Haplopelma lividum. Mature male tarantulas also may have tibial hooks on their front legs, which are used to restrain the female's fangs during copulation.
A juvenile male's sex can be determined by looking at a cast exuvium
for exiandrous fusillae or spermathecae. Females possess spermathecae except for the species Sickius longibulbi and Encyocratella olivacea. Ventral sexing is difficult, but, if done correctly, it can be relatively reliable. Males have much shorter lifespans than females because they die relatively soon after maturing. Few live long enough for a post-ultimate moult. It is unlikely that it happens much in natural habitats because they are vulnerable to predation, but it has happened in captivity if rarely. Most males do not live through this moult as they tend to get their emboli, mature male sexual organs on pedipalps, stuck in the moult. Most tarantula fanciers regard females as more desirable as pets due to their much longer lifespan. Wild caught tarantulas are often mature males because they wander out in the open and are more likely to be caught.
Like other spiders, tarantulas have to shed their exoskeleton
periodically in order to grow, a process called moulting
. A young tarantula may do this several times a year as a part of the maturation process, while full grown specimens will only moult once a year or less, or sooner in order to replace lost limbs or lost urticating hairs. It is clear that moulting will soon occur when the exoskeleton takes on a darker shade. If a tarantula previously used its urticating hairs, the bald patch will turn from a peach color to deep blue.
Tarantulas may live for years—most species taking 2 to 5 years to reach adulthood, but some species may take up to 10 years to reach full maturity. Upon reaching adulthood, males typically have but a 1 to 1.5 year period left to live and will immediately go in search of a female with which to mate. Male tarantulas rarely moult again once they reach adulthood. The oldest spider, according to Guinness World Records
, lived to be 49 years old.
Females will continue to moult after reaching maturity. Female specimens have been known to reach 30 to 40 years of age, and have survived on water alone for up to 2 years. Grammostola rosea spiders are renowned for going for long periods without eating.
As with other spiders, the mechanics of intercourse are quite different from those of mammals. Once a male spider reaches maturity and becomes motivated to mate, it will weave a web mat on a flat surface. The spider will then rub its abdomen on the surface of this mat and in so doing release a quantity of semen. It may then insert its pedipalps (short leg-like appendages between the chelicerae and front legs) into the pool of semen. The pedipalps absorb the semen and keep it viable until a mate can be found. When a male spider detects the presence of a female, the two exchange signals to establish that they are of the same species. These signals may also lull the female into a receptive state. If the female is receptive then the male approaches her and inserts his pedipalps into an opening in the lower surface of her abdomen, called the opisthosoma
. After the semen has been transferred to the receptive female's body, the male will swiftly leave the scene before the female recovers her appetite. Although females may show some aggression after mating, the male rarely becomes a meal.
Females deposit 50 to 2000 eggs, depending on the species, in a silken egg sac and guard it for 6 to 7 weeks. During this time, the female will stay very close to the egg sac and become more aggressive. Within most species, the female turns the egg sac often, which is called brooding. This keeps the eggs from deforming due to sitting too long. The young spiderlings remain in the nest for some time after hatching where they live off the remains of their yolk sac before dispersing.
, containing over 100 genera
and around 900 species
between them.
A few genera are presently not well classified, and/or have classifications which are disputed, including Brachionopus, Cardiopelma, and Proshapalopus
, only two specimens have been found so far which can be convincingly assigned to Theraphosidae. One is from Dominican Republic amber, the other from Chiapas (Mexican) amber. Both these ambers are quite young, being Miocene
in age or about 16 million years old.
Arachnid
Arachnids are a class of joint-legged invertebrate animals in the subphylum Chelicerata. All arachnids have eight legs, although in some species the front pair may convert to a sensory function. The term is derived from the Greek words , meaning "spider".Almost all extant arachnids are terrestrial...
s belonging to the 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...
Theraphosidae, of which approximately 900 species have been identified. Some members of the same Suborder may also be called "tarantulas" in the common parlance. This article will restrict itself to describing members of Theraphosidae. They are also called Athropodes.
Some genera
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
of tarantulas hunt prey primarily in trees; others hunt on or near the ground. All tarantulas can produce silk—while arboreal species will typically reside in a silken "tube tent", terrestrial species will line their burrows with silk to stabilize the burrow wall and facilitate climbing up and down. Tarantulas mainly eat insects and other arthropods, using ambush as their primary method of prey capture. The biggest tarantulas can kill animals as large as lizard
Lizard
Lizards are a widespread group of squamate reptiles, with nearly 3800 species, ranging across all continents except Antarctica as well as most oceanic island chains...
s, mice
Mouse
A mouse is a small mammal belonging to the order of rodents. The best known mouse species is the common house mouse . It is also a popular pet. In some places, certain kinds of field mice are also common. This rodent is eaten by large birds such as hawks and eagles...
, and 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.They can be found in the south and west parts of the USA, Central America, and down throughout South America to the southern parts of Chile, Argentina. Tarantulas can also be found throughout Africa, large parts of Asia and all over Australia. In Europe, there are some species in Spain, Portugal, Turkey, Italy, and in Cyprus. Most tarantulas are harmless to humans, and some species are popular in the exotic pet trade. All tarantulas are venomous, but only some species have venom that, while not known to have ever produced human fatalities, can produce extreme discomfort over a period of several days.
Like all arthropod
Arthropod
An arthropod is an invertebrate animal having an exoskeleton , a segmented body, and jointed appendages. Arthropods are members of the phylum Arthropoda , and include the insects, arachnids, crustaceans, and others...
s, the tarantula is an 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...
that relies on an exoskeleton
Exoskeleton
An exoskeleton is the external skeleton that supports and protects an animal's body, in contrast to the internal skeleton of, for example, a human. In popular usage, some of the larger kinds of exoskeletons are known as "shells". Examples of exoskeleton animals include insects such as grasshoppers...
for muscular support. A tarantula’s body consists of two main parts, the prosoma (cephalothorax) and the opisthosoma
Opisthosoma
The opisthosoma is the posterior part of the body in some arthropods, behind the prosoma . It is a distinctive feature of the subphylum Chelicerata...
(abdomen). The prosoma and opisthosoma are connected by the pedicle
Pedicel (spider)
The pedicel of a spider is a small, flexible cylinder that joins the cephalothorax and abdomen. This helps the spider to spin silk without moving the cephalothorax....
, or what is often called the pregenital somite. This waist-like connecting piece is actually part of the prosoma and allows the opisthosoma to move in a wide range of motion relative to the prosoma.
The sizes range from as small as a fingernail to as big as a dinner plate. Depending on the species, the body length of tarantulas ranges from 2.5 to 10 cm (0.984251968503937 to 3.9 ), with 8–30 cm (3.1–11.8 ) leg spans. Leg span is determined by measuring from the tip of the back leg to the tip of the front leg on the opposite side. The largest species of tarantula can weigh over 85 grams (3 oz). The largest of all, the Goliath Birdeater
Goliath birdeater
The Goliath bird-eater Spider is an arachnid belonging to the tarantula group, Theraphosidae, and is considered to be the second largest spider in the world , and they may be the biggest by mass...
(Theraphosa blondi) from Venezuela and Brazil, has been reported to have a weight of 150 grams (5.3 oz) and a leg-span of up to 30 centimetres (11.8 in), males being the longer and females greater in girth.
T. apophysis (the Pinkfoot Goliath) was described 187 years after the Goliath Birdeater; therefore its characteristics are not as well attested.T. blondi is generally thought to be the heaviest tarantula, and T. apophysis to have the greatest leg span. Two other species, Lasiodora parahybana
Lasiodora parahybana
The Brazilian Salmon Pink Bird-eating Tarantula is a relatively large spider originating from northeastern Brazil, hence its common name. This spider typically grows to a leg span of 20 cm , although occasionally exceptional specimens can reach leg spans of 25 cm . Large females can...
(the Brazilian Salmon Birdeater) and L. klugi, rival the size of the two Goliath spiders.
The majority of North American tarantulas are brown. Elsewhere have been found species colored cobalt blue (Haplopelma lividum
Cobalt blue tarantula
The cobalt blue tarantula is a tarantula species that is native to Myanmar and Thailand.-Description:The cobalt blue tarantula is a medium size tarantula with a leg span of approximately 13 cm . The cobalt blue tarantula is noted for its iridescent blue legs and light gray prosoma and...
), black with white stripes (Aphonopelma seemanni
Aphonopelma seemanni
The Costa Rican Zebra Tarantula, also known as the Striped-knee Tarantula , inhabits most of western Costa Rica, as well as other parts of Central America, such as Guatemala, Honduras and Nicaragua. It is black with white stripes near the joint. Specimens from Nicaragua are tan-coloured.Zebra...
), yellow leg markings (Eupalaestrus campestratus
Eupalaestrus campestratus
The Pink Zebra Beauty is a terrestrial tarantula native to Brazil, Paraguay, and Argentina. It is known for its docile and tolerant temperament and is therefore an attractive pet tarantula...
), metallic blue legs with vibrant orange abdomen and greenbottle blue (Chromatopelma cyaneopubescens
Greenbottle blue tarantula
The Greenbottle Blue Tarantula , a native of Venezuela, has some of the most dramatic coloring of any spider species...
). Their natural habitats include savanna
Savanna
A savanna, or savannah, is a grassland ecosystem characterized by the trees being sufficiently small or widely spaced so that the canopy does not close. The open canopy allows sufficient light to reach the ground to support an unbroken herbaceous layer consisting primarily of C4 grasses.Some...
, grassland
Grassland
Grasslands are areas where the vegetation is dominated by grasses and other herbaceous plants . However, sedge and rush families can also be found. Grasslands occur naturally on all continents except Antarctica...
s such as the pampa
Pampa
The Pampas are the fertile South American lowlands, covering more than , that include the Argentine provinces of Buenos Aires, La Pampa, Santa Fe, Entre Ríos and Córdoba, most of Uruguay, and the southernmost Brazilian State, Rio Grande do Sul...
s, rainforest
Rainforest
Rainforests are forests characterized by high rainfall, with definitions based on a minimum normal annual rainfall of 1750-2000 mm...
s, desert
Desert
A desert is a landscape or region that receives an extremely low amount of precipitation, less than enough to support growth of most plants. Most deserts have an average annual precipitation of less than...
s, scrubland, mountain
Mountain
Image:Himalaya_annotated.jpg|thumb|right|The Himalayan mountain range with Mount Everestrect 58 14 160 49 Chomo Lonzorect 200 28 335 52 Makalurect 378 24 566 45 Mount Everestrect 188 581 920 656 Tibetan Plateaurect 250 406 340 427 Rong River...
s, and cloud forest
Cloud forest
A cloud forest, also called a fog forest, is a generally tropical or subtropical evergreen montane moist forest characterized by a persistent, frequent or seasonal low-level cloud cover, usually at the canopy level. Cloud forests often exhibit an abundance of mosses covering the ground and...
s. They are generally classed among the terrestrial types. They are burrowers that live in the ground.
Tarantulas are becoming increasingly popular as pets and are readily available in captivity.
Etymology
The word "tarantula" has been applied to several very different kinds of spiderSpider
Spiders are air-breathing arthropods that have eight legs, and chelicerae with fangs that inject venom. They are the largest order of arachnids and rank seventh in total species diversity among all other groups of organisms...
. The spider originally bearing that name is one of the wolf spider
Wolf spider
Wolf spiders are members of the family Lycosidae, from the Ancient Greek word "" meaning "wolf". They are robust and agile hunters with good eyesight. They live mostly solitary lives and hunt alone. Some are opportunistic hunters pouncing upon prey as they find it or even chasing it over short...
s, Lycosa tarantula
Lycosa tarantula
The tarantula wolf spider or just tarantula is a wolf spider found in southern Europe, especially in Italy and near the city of Taranto...
, found in the region surrounding the southern Italian
Italy
Italy , officially the Italian Republic languages]] under the European Charter for Regional or Minority Languages. In each of these, Italy's official name is as follows:;;;;;;;;), is a unitary parliamentary republic in South-Central Europe. To the north it borders France, Switzerland, Austria and...
town of Taranto
Taranto
Taranto is a coastal city in Apulia, Southern Italy. It is the capital of the Province of Taranto and is an important commercial port as well as the main Italian naval base....
. Compared to new-world tarantulas, wolf spiders are not particularly large or hairy.
Tarantism
The bite of L. tarantula was once believed to cause a fatal condition called tarantismTarantism
Tarantism is an alleged, possibly deadly envenomation, popularly believed to result from the bite of a kind of wolf spider called a "tarantula"...
, whose cure was believed to involve wild dancing of a kind that has come to be identified with the tarantella
Tarantella
The term tarantella groups a number of different southern Italian couple folk dances characterized by a fast upbeat tempo, usually in 6/8 time , accompanied by tambourines. It is among the most recognized of traditional Italian music. The specific dance name varies with every region, for instance...
. However, modern research has shown that the bite of L. tarantula is generally not dangerous to human beings. There appears to have existed a different species of spider in the fields around Taranto responsible for fairly severe bites. The likely candidate (and the only spider found in the area which is dangerous to man) is the malmignatte or Mediterranean black widow
Latrodectus tredecimguttatus
Latrodectus tredecimguttatus, commonly known as the Mediterranean black widow or steppe spider, is a species of widow spiders in the genus Latrodectus. It is commonly found throughout the Mediterranean region, ranging from Spain to southwest and central Asia, hence the name...
. This spider, which belongs in the genus Latrodectus
Widow spider
Latrodectus is a genus of spider, in the family Theridiidae, which contains 31 recognized species. The common name widow spiders is sometimes applied to members of the genus due to the behavior of the female of eating the male after mating, although sometimes the males of some species are not eaten...
, is a close relative of the black widow
Black widow spider
Latrodectus mactans, the Southern black widow, is a highly venomous species of spider in the genus Latrodectus. They are well known for the distinctive black and red coloring of the female of the species and for the fact that she will occasionally eat her mate after reproduction. The species is...
and redback spiders, and has a bite which is medically significant
Spider bite
A spider bite is an injury resulting from the bites of spiders or other closely related arachnids.Spiders are active hunters and rely heavily on their bites to paralyze and kill their prey before consuming it. They also bite in self defense...
. However, Lycosa tarantula, being larger and more fearsome-looking, tended to be unjustly credited with any severe bites.
New-world and other divergent usages
When theraphosids were encountered in the AmericasAmericas
The Americas, or America , are lands in the Western hemisphere, also known as the New World. In English, the plural form the Americas is often used to refer to the landmasses of North America and South America with their associated islands and regions, while the singular form America is primarily...
, they were named "tarantulas", causing usage of the term to shift to the tropical spiders. Nevertheless, these spiders belong to the suborder Mygalomorphae
Mygalomorphae
The Mygalomorphae, , are an infraorder of spiders. The latter name comes from the orientation of the fangs which point straight down and do not cross each other .-Description:...
, and are not closely related to wolf spiders.
The name "tarantula" is also mistakenly applied to other large-bodied spiders, including the purseweb spiders or atypical tarantula
Atypical tarantula
The atypical tarantulas or purseweb spiders consist of only three genera. Purseweb spiders are accomplished ambush predators that spend most of their time in a sock-like, silken retreat on the ground from where they kill their prey....
s, the funnel-webs (Dipluridae
Dipluridae
Funnel-web tarantulas , are a group of spiders in the infraorder Mygalomorphae, that have two pairs of booklungs, and chelicerae that move up and down in a stabbing motion...
and Hexathelidae
Hexathelidae
The spider family Hexathelidae, the only family in the super-family Hexatheloidea, is one of two families of spiders known as funnel-webs...
), and the "dwarf tarantula
Dwarf tarantula
Dwarf tarantulas, also known as sheet funnel-web spiders are a type of spider from the family Mecicobothriidae. Dwarf tarantulas are one of several families of the sub-order Mygalomorphae; this larger group also includes the true tarantulas....
s". These spiders are related to tarantulas (all being mygalomorphs), but are classified in different families
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...
. Huntsman spider
Huntsman spider
Sparassidae are a family of spiders known as Huntsman spiders because of their speed and mode of hunting. They also are called giant crab spiders, because of their size and appearance. Larger species sometimes are referred to as wood spiders, because of their preference for woody places...
s of the family Sparassidae have also been termed "tarantulas" because of their large size. In fact, they are not related, belonging to the suborder Araneomorphae
Araneomorphae
The Araneomorphae are a suborder of spiders. They are distinguished by having fangs that oppose each other and cross in a pinching action, in contrast to the Mygalomorphae , which have fangs that are nearly parallel in alignment.- Distinguishing characteristics :Note the difference in the...
.
Appendages
Chelicerae
The chelicerae are mouthparts of the Chelicerata, an arthropod subphylum that includes arachnids, Merostomata , and Pycnogonida . Chelicerae are pointed appendages which are used to grasp food, and are found in place of the chewing mandibles most other arthropods have...
with their fangs, and the pedipalp
Pedipalp
Pedipalps , are the second pair of appendages of the prosoma in the subphylum Chelicerata. They are traditionally thought to be homologous with mandibles in Crustacea and insects, although more recent studies Pedipalps (commonly shortened to palps or palpi), are the second pair of appendages of the...
s are attached to the prosoma. The chelicerae are two double segment appendages that are located just below the eyes and directly forward of the mouth. The chelicerae contain the venom glands that vent through the fangs. The fangs are hollow extensions of the chelicerae that inject venom into prey or animals that the tarantula bites in defense, and they are also used to masticate. These fangs are articulated so that they can extend downward and outward in preparation to bite or can fold back toward the chelicerae as a pocket knife blade folds back into its handle. The chelicerae of a tarantula completely contain the venom glands and the muscles that surround them, and can cause the venom to be forcefully injected into prey.
The pedipalpi are two six-segment appendages connected to the thorax
Thorax
The thorax is a division of an animal's body that lies between the head and the abdomen.-In tetrapods:...
near the mouth and protruding on either side of both chelicerae. In most species of tarantula, the pedipalpi contain sharp jagged plates used to cut and crush food often called the coxae
Arthropod leg
The arthropod leg is a form of jointed appendage of arthropods, usually used for walking. Many of the terms used for arthropod leg segments are of Latin origin, and may be confused with terms for bones: coxa , trochanter , femur, tibia, tarsus, ischium, metatarsus, carpus, dactylus ,...
or maxillae
Mouthparts
The mouthparts of arthropods have evolved into a number of forms, each adapted to a different style or mode of feeding. Most mouthparts represent modified, paired appendages, which in ancestral forms would have appeared more like legs than mouthparts. In general, arthropods have mouthparts for...
. As with other spiders, the terminal portion of the pedipalpi of males function as part of its reproductive system. Male spiders spin a silken platform (sperm web) on the ground onto which they release semen from glands in their opistoma. Then they insert their pedipalps into the semen, absorb the semen into the pedipalps, and later insert the pedipalps (one at a time) into the reproductive organ of the female, which is located in her abdomen. The terminal segments of the pedipalps of male tarantulas are moderately larger in circumference than those of a female tarantula. Male tarantulas have special spinnerets surrounding the genital opening. Silk for the sperm web of the tarantula is exuded from these special spinnerets.
Tarantulas, like almost all other spiders, have their primary spinnerets at the end of the opisthosoma. Unlike the typical spiders that on average have six, tarantulas have two or four spinnerets. Spinnerets are flexible tubelike structures from which the spider exudes its silk. The tip of each spinneret is called the spinning field. Each spinning field is covered by as many as one hundred spinning tubes through which silk is exuded. This silk hardens on contact with the air to become a threadlike substance.
Silk-producing feet
It was discovered that some tarantulas have silk-producing spigots on their feet. As the research subjects used to make this discovery, which was first proposed in 2006, varied widely, Dr Claire Rind of the University of NewcastleUniversity of Newcastle
University of Newcastle can refer to:* Newcastle University, a university in the United Kingdom* University of Newcastle, Australia, a university in New South Wales...
suggests that it is likely that all tarantulas have the ability to produce silk from their tarsi (feet). The existence of these structures is thought to enable the spiders to cling to smooth surfaces and thus avoid a harmful fall. The discovery was published in the Journal of Experimental Biology.
Digestive system
The tarantula's digestive organ (stomach) is a tube that runs the length of its body. In the prosoma, this tube is wider and forms the sucking stomach. When the sucking stomach's powerful muscles contract, the stomach is increased in cross-section, creating a strong sucking action that permits the tarantula to suck its liquefied prey up through the mouth and into the intestines. Once the liquefied food enters the intestines, it is broken down into particles small enough to pass through the intestine walls into the hemolymph
Hemolymph
Hemolymph, or haemolymph, is a fluid in the circulatory system of some arthropods and is analogous to the fluids and cells making up both blood and interstitial fluid in vertebrates such as birds and mammals...
(blood stream) where it is distributed throughout the body. After feeding, the leftovers are formed into a small ball by the tarantula and thrown away. In a terrarium, they often put them into the same corner. As these balls are perfect hosts for mold
Mold
Molds are fungi that grow in the form of multicellular filaments called hyphae. Molds are not considered to be microbes but microscopic fungi that grow as single cells called yeasts...
s and parasites, they must be removed regularly.
Nervous system
A tarantula's central nervous system (brain) is located in the bottom of the inner prosomaCephalothorax
The cephalothorax is a tagma of various arthropods, comprising the head and the thorax fused together, as distinct from the abdomen behind. The word cephalothorax is derived from the Greek words for head and thorax...
. A tarantula perceives its surroundings primarily via sensory organs called seta
Seta
Seta is a biological term derived from the Latin word for "bristle". It refers to a number of different bristle- or hair-like structures on living organisms.-Animal setae:In zoology, most "setae" occur in invertebrates....
e (hairs or spines). Although a tarantula has eyes, touch is its keenest sense, and in hunting it primarily depends on vibrations given off by the movements of its prey. A tarantula's setae are very sensitive organs and are used to sense chemical signatures, vibrations, wind direction, and possibly even sound. Tarantulas are also very responsive to the presence of certain chemicals such as pheromone
Pheromone
A pheromone is a secreted or excreted chemical factor that triggers a social response in members of the same species. Pheromones are chemicals capable of acting outside the body of the secreting individual to impact the behavior of the receiving individual...
s.
Respiratory system
In all types of tarantula there are two sets of book lungBook lung
A book lung is a type of respiration organ used for atmospheric gas exchange and is found in arachnids, such as scorpions and spiders. Each of these organs is found inside a ventral abdominal cavity and connects with the surroundings through a small opening. Book lungs are not related to the lungs...
s (breathing organs). The first pair of book lungs is located in a cavity inside the lower front part of the abdomen near where the abdomen connects to the cephalothorax and the second pair slightly farther back on the abdomen. Air enters the cavity through a tiny slit on each side of and near the front of the abdomen. Each lung consists of 15 or more thin sheets of folded tissue arranged like the pages of a book. These sheets of tissue are supplied by blood vessels. As air enters each lung, oxygen is taken into the blood stream through the blood vessels in the lungs. Needed moisture may also be absorbed from humid air by these organs.
Circulatory system
Hemocyanin
Hemocyanins are respiratory proteins in the form of metalloproteins containing two copper atoms that reversibly bind a single oxygen molecule . Oxygenation causes a color change between the colorless Cu deoxygenated form and the blue Cu oxygenated form...
) but not enclosed in blood cells such as the erythrocytes of mammals. A tarantula’s blood is not true blood but rather a liquid called haemolymph, or hemolymph. There are at least four types of hemocytes, or hemolymph cells. The tarantula’s heart is a long slender tube that is located along the top of the opisthosoma. The heart is neurogenic as opposed to myogenic, so nerve cells instead of muscle cells initiate and coordinate the heart. The heart pumps hemolymph to all parts of the body through open passages often referred to as sinuses, and not through a circular system of blood vessels. If the exoskeleton is breached, loss of hemolymph will kill the tarantula unless the wound is small enough that the hemolymph can dry and close the wound.
Predators
Regardless of their fearsome reputation, tarantulas are themselves an object of predation, the most specialized of these predators are large members of the wasp family Pompilidae. In the Americas, these insects are termed "tarantula hawks", being parasitoidParasitoid
A parasitoid is an organism that spends a significant portion of its life history attached to or within a single host organism in a relationship that is in essence parasitic; unlike a true parasite, however, it ultimately sterilises or kills, and sometimes consumes, the host...
s of tarantulas. The largest tarantula hawks, such as those in the genus Pepsis, will track, attack and kill large tarantulas. They use olfaction
Olfaction
Olfaction is the sense of smell. This sense is mediated by specialized sensory cells of the nasal cavity of vertebrates, and, by analogy, sensory cells of the antennae of invertebrates...
to find the lair of a tarantula. The wasp must deliver a sting to the underside of the spider's cephalothorax, exploiting the thin membrane between the basal leg segments. This paralyzes the spider and the wasp then drags it back into its burrow before depositing an egg on the prey's abdomen. The wasp then seals the spider in its burrow and flies off to search for more hosts. The wasp larva hatches and feeds on the spider's non-essential parts and, as it approaches pupation, it consumes the remainder. In addition to more mundane cuisine, tarantulas are considered a delicacy in certain cultures (e.g., Cambodia). They are usually roasted over an open fire to remove the hair and then eaten.
Urticating hair
Urticating hairs, i.e. stinging hairs, are one of the primary defense mechanisms used by numerous plants, some New World tarantulas, and various lepidopteran caterpillars. Urtica is Latin for "nettle", and hairs that urticate are characteristic of this type of plant, and many other plants in...
s, on the opisthosoma, that they sometimes use as protection against enemies. These hairs are present on new-world
New World
The New World is one of the names used for the Western Hemisphere, specifically America and sometimes Oceania . The term originated in the late 15th century, when America had been recently discovered by European explorers, expanding the geographical horizon of the people of the European middle...
species but not on specimens from the Old World
Old World
The Old World consists of those parts of the world known to classical antiquity and the European Middle Ages. It is used in the context of, and contrast with, the "New World" ....
.
Urticating hairs are usually kicked off the abdomen by the tarantula, but it is noteworthy that some may simply rub the abdomen against the target, such is so with the Avicularia
Avicularia
Avicularia is a genus of the family Theraphosidae containing various species of tarantulas. The genus is native to tropical South America. Each species in the genus has very distinguishable pink foot pads....
genera. These fine hairs are barbed and serve to irritate. They can be lethal to small animals such as rodents. Some people are extremely sensitive to these hairs, and develop serious itching and rashes at the site. Exposure of the eyes and respiratory system to urticating hairs should be strictly avoided. Species with urticating hairs can kick these hairs off: they are flicked into the air at a target using their back pairs of legs. Tarantulas also use these hairs for other purposes such as to mark territory or to line their shelters (the latter such practice may discourage flies
Fly
True flies are insects of the order Diptera . They possess a pair of wings on the mesothorax and a pair of halteres, derived from the hind wings, on the metathorax...
from feeding on the spiderlings). Urticating hairs do not grow back, but are replaced with each moult
Moult
In biology, moulting or molting , also known as sloughing, shedding, or for some species, ecdysis, is the manner in which an animal routinely casts off a part of its body , either at specific times of year, or at specific points in its life cycle.Moulting can involve the epidermis , pelage...
. The intensity, amount, and flotation of the hairs depends on the species of tarantula. Many owners of Goliath Birdeaters (T. blondi) claim that theraphosids have the worst urticating hairs..
To predators and other kinds of enemies, these hairs can range from being lethal to simply being a deterrent. With humans, they can cause irritation to eyes, nose, and skin, and more dangerously, the lungs and airways, if inhaled. The symptoms range from species to species, from person to person, from a burning itch to a minor rash. In some cases, tarantula hairs have caused permanent damage to human eyes.
Some setae are used to stridulate, which makes a hissing sound. These hairs are usually found on the chelicerae. Stridulation
Stridulation
Stridulation is the act of producing sound by rubbing together certain body parts. This behavior is mostly associated with insects, but other animals are known to do this as well, such as a number of species of fishes, snakes and spiders...
seems to be more common in old-world species.
Bites and Urticating Hairs
Despite their often threatening appearance and reputation, no tarantula has been known to have a biteSpider bite
A spider bite is an injury resulting from the bites of spiders or other closely related arachnids.Spiders are active hunters and rely heavily on their bites to paralyze and kill their prey before consuming it. They also bite in self defense...
that is deadly to humans. In general, the effects of the bites of all kinds of tarantula are not well known. While the bites of many species are known to be no worse than a wasp sting, accounts of bites by some species are reported to be very painful and to produce intense spasms that may recur over a period of several days; the venom by the African tarantula Pelinobius muticus also causes strong hallucinations. In all cases, it is prudent to seek medical aid. Because other proteins are included when a toxin
Toxin
A toxin is a poisonous substance produced within living cells or organisms; man-made substances created by artificial processes are thus excluded...
is injected, some individuals may suffer severe symptoms due to an allergic reaction rather than to the venom. Such allergic effects can be life-threatening.
Before biting, tarantulas may signal their intention to attack by rearing up into a "threat posture", which may involve raising their prosoma and lifting their front legs into the air, spreading and extending their fangs, and (in certain species) making a loud hissing by stridulating
Stridulation
Stridulation is the act of producing sound by rubbing together certain body parts. This behavior is mostly associated with insects, but other animals are known to do this as well, such as a number of species of fishes, snakes and spiders...
. Their next step, short of biting, may be to slap down on the intruder with their raised front legs. If that response fails to deter the attacker, the tarantulas of the Americas may next turn away and flick urticating hairs toward the pursuing predator. The next response may be to leave the scene entirely, but, especially if there is no line of retreat, their final response may also be to whirl suddenly and bite. Some tarantulas are well known to give "dry bites," i.e., they may defensively bite some animal that intrudes on their space and threatens them, but they will not pump venom into the wound.
New-world tarantulas (those found in North
North America
North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...
and South America
South America
South America is a continent situated in the Western Hemisphere, mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere. The continent is also considered a subcontinent of the Americas. It is bordered on the west by the Pacific Ocean and on the north and east...
) are equipped with urticating hair
Urticating hair
Urticating hairs, i.e. stinging hairs, are one of the primary defense mechanisms used by numerous plants, some New World tarantulas, and various lepidopteran caterpillars. Urtica is Latin for "nettle", and hairs that urticate are characteristic of this type of plant, and many other plants in...
s on their abdomen, and will almost always throw
Projectile use by living systems
Although projectiles are commonly used in human conflict, projectile use by living systems other than humans is relatively rare.-Liquid projectiles:...
these barbed hairs as a first line of defense. These hairs will irritate sensitive areas of the body and especially seem to target curious animals who may sniff these hairs into the mucous membranes of the nose. Some species have more effective urticating hairs than others. The Goliath Birdeater is one species known for its particularly irritating urticating hairs. Urticating hairs can penetrate the cornea
Cornea
The cornea is the transparent front part of the eye that covers the iris, pupil, and anterior chamber. Together with the lens, the cornea refracts light, with the cornea accounting for approximately two-thirds of the eye's total optical power. In humans, the refractive power of the cornea is...
so eye protection should be worn when handling such tarantulas.
Old-world tarantulas (from Europe, Africa, Asia and Australia) have no urticating hairs and are more likely to attack when disturbed. Old-world tarantulas often have more potent, medically significant venom.
There are dangerous spider species which are related to tarantulas and frequently confused with them. A popular urban legend
Urban legend
An urban legend, urban myth, urban tale, or contemporary legend, is a form of modern folklore consisting of stories that may or may not have been believed by their tellers to be true...
maintains that deadly varieties of tarantula exist somewhere in South America. This claim is often made without identifying a particular spider, although the "banana tarantula" is sometimes named. A likely candidate for the true identity of this spider is the dangerous Brazilian wandering spider
Brazilian wandering spider
Phoneutria, commonly known as Brazilian wandering spiders, armed spiders , or banana spiders , are a genus of aggressive and highly venomous spiders found in tropical South and Central America...
Phoneutria nigriventer, of the family Ctenidae
Wandering spider
The wandering spiders is a term used to refer to the spider family Ctenidae. Previously, the term referred only to the genus Phoneutria but now usually refers to the entire family Ctenidae. The members of the genus Phoneutria are highly aggressive and venomous nocturnal hunters, and are the only...
, as it is sometimes found hiding in clusters of bananas and is one of several spiders called the "banana spider." It is not technically a tarantula but it is fairly large (4–5 inches long), somewhat hairy, and is highly venomous to humans. Another dangerous type of spider that has been confused with tarantulas is the Australasian funnel-web spider
Australasian funnel-web spider
Australian funnel-web spiders are venomous spiders of the family Hexathelidae, represented by 31 described species of Hadronyche, four Bymainiella spp., two Teranodes and monotyptic genera Plesiothera fentoni and Ilawarra whisharti...
. The best known of these is the Sydney funnel-web spider Atrax robustus, a spider that is aggressive, highly venomous, and (prior to the development of antivenin
Antivenin
Antivenom is a biological product used in the treatment of venomous bites or stings. Antivenom is created by milking venom from the desired snake, spider or insect. The venom is then diluted and injected into a horse, sheep or goat...
in the 1980s) was responsible for numerous deaths in Australia
Australia
Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...
. These spiders are members of the same suborder as tarantulas. (Some Australians use the slang term 'triantelope' for large, hairy, and harmless members of the Huntsman spider
Huntsman spider
Sparassidae are a family of spiders known as Huntsman spiders because of their speed and mode of hunting. They also are called giant crab spiders, because of their size and appearance. Larger species sometimes are referred to as wood spiders, because of their preference for woody places...
family which are often found on interior household walls and in automobiles.)
Medical implications
While no fatalities have been attributed to tarantula bitesSpider bite
A spider bite is an injury resulting from the bites of spiders or other closely related arachnids.Spiders are active hunters and rely heavily on their bites to paralyze and kill their prey before consuming it. They also bite in self defense...
, sometimes spider bites are regarded as the probable source of infections. Medical advice regarding prophylaxis may be helpful in that regard. In addition, there is considerable anecdotal evidence indicating that the venoms of some old-world species can produce symptoms so severe that medical treatment would be appropriate. Medical intervention is also regarded as appropriate when symptoms such as breathing difficulty or chest pain develop, since these conditions may indicate an anaphylactic
Anaphylaxis
Anaphylaxis is defined as "a serious allergic reaction that is rapid in onset and may cause death". It typically results in a number of symptoms including throat swelling, an itchy rash, and low blood pressure...
reaction. As with bee sting
Bee sting
A bee sting is strictly a sting from a bee . In the vernacular it can mean a sting of a bee, wasp, hornet, or yellow jacket. Some people may even call the bite of a horse-fly a bee sting...
s, allergic reactions to protein fractions may be many times more dangerous than the direct toxic effects of the venom.
Urticating hairs may cause medical problems for humans should they enter the eyes or the respiratory system. Unless one inhales air heavily laden with these hairs or rubs them into one's eyes, they are rarely a problem. Some individuals are more sensitive to skin contact with these spines and learn to avoid them when cleaning cages or otherwise coming into potential contact with them.
Sexual dimorphism
Some tarantula species exhibit pronounced sexual dimorphismSexual 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:...
. Males tend to be smaller (especially their abdomens, which can appear quite narrow) and may be dull in color when compared to their female counterparts, as in the species Haplopelma lividum. Mature male tarantulas also may have tibial hooks on their front legs, which are used to restrain the female's fangs during copulation.
A juvenile male's sex can be determined by looking at a cast exuvium
Exuvia
Exuviae is a term used in biology to describe the remains of an exoskeleton and related structures that are left after ecdysozoans have moulted...
for exiandrous fusillae or spermathecae. Females possess spermathecae except for the species Sickius longibulbi and Encyocratella olivacea. Ventral sexing is difficult, but, if done correctly, it can be relatively reliable. Males have much shorter lifespans than females because they die relatively soon after maturing. Few live long enough for a post-ultimate moult. It is unlikely that it happens much in natural habitats because they are vulnerable to predation, but it has happened in captivity if rarely. Most males do not live through this moult as they tend to get their emboli, mature male sexual organs on pedipalps, stuck in the moult. Most tarantula fanciers regard females as more desirable as pets due to their much longer lifespan. Wild caught tarantulas are often mature males because they wander out in the open and are more likely to be caught.
Life cycle
Exoskeleton
An exoskeleton is the external skeleton that supports and protects an animal's body, in contrast to the internal skeleton of, for example, a human. In popular usage, some of the larger kinds of exoskeletons are known as "shells". Examples of exoskeleton animals include insects such as grasshoppers...
periodically in order to grow, a process called moulting
Ecdysis
Ecdysis is the moulting of the cuticula in many invertebrates. This process of moulting is the defining feature of the clade Ecdysozoa, comprising the arthropods, nematodes, velvet worms, horsehair worms, rotifers, tardigrades and Cephalorhyncha...
. A young tarantula may do this several times a year as a part of the maturation process, while full grown specimens will only moult once a year or less, or sooner in order to replace lost limbs or lost urticating hairs. It is clear that moulting will soon occur when the exoskeleton takes on a darker shade. If a tarantula previously used its urticating hairs, the bald patch will turn from a peach color to deep blue.
Tarantulas may live for years—most species taking 2 to 5 years to reach adulthood, but some species may take up to 10 years to reach full maturity. Upon reaching adulthood, males typically have but a 1 to 1.5 year period left to live and will immediately go in search of a female with which to mate. Male tarantulas rarely moult again once they reach adulthood. The oldest spider, according to Guinness World Records
Guinness World Records
Guinness World Records, known until 2000 as The Guinness Book of Records , is a reference book published annually, containing a collection of world records, both human achievements and the extremes of the natural world...
, lived to be 49 years old.
Females will continue to moult after reaching maturity. Female specimens have been known to reach 30 to 40 years of age, and have survived on water alone for up to 2 years. Grammostola rosea spiders are renowned for going for long periods without eating.
Reproduction
Opisthosoma
The opisthosoma is the posterior part of the body in some arthropods, behind the prosoma . It is a distinctive feature of the subphylum Chelicerata...
. After the semen has been transferred to the receptive female's body, the male will swiftly leave the scene before the female recovers her appetite. Although females may show some aggression after mating, the male rarely becomes a meal.
Females deposit 50 to 2000 eggs, depending on the species, in a silken egg sac and guard it for 6 to 7 weeks. During this time, the female will stay very close to the egg sac and become more aggressive. Within most species, the female turns the egg sac often, which is called brooding. This keeps the eggs from deforming due to sitting too long. The young spiderlings remain in the nest for some time after hatching where they live off the remains of their yolk sac before dispersing.
Taxonomy
The family Theraphosidae is divided up into 12 subfamiliesFamily (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...
, containing over 100 genera
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
and around 900 species
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
between them.
- Acanthopelminae, first described by Frederick Octavius Pickard-CambridgeFrederick Octavius Pickard-CambridgeFrederick Octavius Pickard-Cambridge was an English arachnologist. He is often confused with his uncle, Octavius Pickard-Cambridge , who was also an arachnologist and from whom F. O. Pickard-Cambridge picked up his enthusiasm for the study of spiders.-Life:F. O. Pickard-Cambridge was born in...
in 1897, is a subfamily of small, terrestrial new-world tarantulas. This subfamily has only one genus, Acanthopelma, and two species, A. beccarri and A. rufescens, found in GuyanaGuyanaGuyana , officially the Co-operative Republic of Guyana, previously the colony of British Guiana, is a sovereign state on the northern coast of South America that is culturally part of the Anglophone Caribbean. Guyana was a former colony of the Dutch and of the British...
and Central AmericaCentral AmericaCentral America is the central geographic region of the Americas. It is the southernmost, isthmian portion of the North American continent, which connects with South America on the southeast. When considered part of the unified continental model, it is considered a subcontinent...
.
- Aviculariinae is a subfamily of tropical, tree-dwelling new-world tarantulas. They range from the CaribbeanCaribbeanThe Caribbean is a crescent-shaped group of islands more than 2,000 miles long separating the Gulf of Mexico and the Caribbean Sea, to the west and south, from the Atlantic Ocean, to the east and north...
to South AmericaSouth AmericaSouth America is a continent situated in the Western Hemisphere, mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere. The continent is also considered a subcontinent of the Americas. It is bordered on the west by the Pacific Ocean and on the north and east...
, and are commonly known as "pinktoe" tarantulas. The genera AviculariaAviculariaAvicularia is a genus of the family Theraphosidae containing various species of tarantulas. The genus is native to tropical South America. Each species in the genus has very distinguishable pink foot pads....
, Ephebopus, and Pachistopelma possess urticating hairs, but cannot "flick" them into the air; instead the hairs are pressed into an enemy upon contact.
- Eumenophorinae is a subfamily of old-world tarantulas, mostly from AfricaAfricaAfrica is the world's second largest and second most populous continent, after Asia. At about 30.2 million km² including adjacent islands, it covers 6% of the Earth's total surface area and 20.4% of the total land area...
and surrounding regions. In addition, some authors place genus Proshapalopus (a genus found in BrazilBrazilBrazil , officially the Federative Republic of Brazil , is the largest country in South America. It is the world's fifth largest country, both by geographical area and by population with over 192 million people...
, and not in Africa) in this sub-family.
- HarpactirinaeHarpactirinaeHarpactirinae are a subfamily of old-world tarantulas which are native to the continent of Africa. Like many old-world tarantulas, they have a strong venom, and can inflict a painful bite; however most baboon spiders are not considered dangerous to man...
is a group of old-world tarantulas from AfricaAfricaAfrica is the world's second largest and second most populous continent, after Asia. At about 30.2 million km² including adjacent islands, it covers 6% of the Earth's total surface area and 20.4% of the total land area...
, though smaller than Eumenophorinae. They are known as baboon spiders for their hairy legs and the thick black scorpulae at the end of their feet, which are said to resemble baboonBaboonBaboons are African and Arabian Old World monkeys belonging to the genus Papio, part of the subfamily Cercopithecinae. There are five species, which are some of the largest non-hominoid members of the primate order; only the mandrill and the drill are larger...
s.
- Ischnocolinae contains spiders from around the world.
- The "earth tigers" of subfamily OrnithoctoninaeOrnithoctoninaeOrnithoctoninae, also known as earth tigers, are a subfamily of old-world tarantulas, which were first erected in 1895 by Reginald Innes Pocock on basis of the genotype Ornithoctonus andersoni described in 1892 from former Burma, now Myanmar....
form a group of old-world tarantulas which are found primarily in Southeast AsiaSoutheast AsiaSoutheast Asia, South-East Asia, South East Asia or Southeastern Asia is a subregion of Asia, consisting of the countries that are geographically south of China, east of India, west of New Guinea and north of Australia. The region lies on the intersection of geological plates, with heavy seismic...
, southern ChinaChinaChinese civilization may refer to:* China for more general discussion of the country.* Chinese culture* Greater China, the transnational community of ethnic Chinese.* History of China* Sinosphere, the area historically affected by Chinese culture...
, and BorneoBorneoBorneo is the third largest island in the world and is located north of Java Island, Indonesia, at the geographic centre of Maritime Southeast Asia....
. This group includes the infamous Chinese bird spiderChinese bird spiderChinese bird spider is an English name given to several species of old-world tarantulas which are found in the People's Republic of China and Vietnam. The spider, also known in English as the earth tiger, is currently classified in the genus Haplopelma...
.
- PoecilotheriinaePoecilotheriaPoecilotheria is a genus of the family Theraphosidae containing various species of arboreal tarantula. This genus is known for vivid color patterns, fast movement, and potent venom compared to other tarantulas. The genus is native to Sri Lanka and India. The name Poecilotheria is derived from...
are tree spiders from India and Sri Lanka, some of which are considered endangeredEndangered speciesAn 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...
. This subfamily contains only a single genus.
- Selenocosmiinae is a subfamily which consists mainly of tarantulas from East Asia and AustraliaAustraliaAustralia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...
. Like the East Asian tarantulas in OrnithoctoninaeOrnithoctoninaeOrnithoctoninae, also known as earth tigers, are a subfamily of old-world tarantulas, which were first erected in 1895 by Reginald Innes Pocock on basis of the genotype Ornithoctonus andersoni described in 1892 from former Burma, now Myanmar....
, these are known for their strong venom and defensive disposition. The genera Psalmopoeus and Tapinauchenius do not have urticating hairs, unusual among new-world species.
- Selenogyrinae is a subfamily of tarantulas from India and Africa.
- Stromatopelminae are tree-dwelling tarantulas from western Africa.
- TheraphosinaeTheraphosinaeTheraphosinae is a large subfamily of Mygalomorphae spiders in the Theraphosidae family.- References :; ; 2011: Revalidation of Pterinopelma Pocock 1901 with description of a new species and the female of Pterinopelma vitiosum . Zootaxa, 2814: 1–18...
are new-world terrestrial tarantulas with urticating hairUrticating hairUrticating hairs, i.e. stinging hairs, are one of the primary defense mechanisms used by numerous plants, some New World tarantulas, and various lepidopteran caterpillars. Urtica is Latin for "nettle", and hairs that urticate are characteristic of this type of plant, and many other plants in...
s. The majority of spiders kept as pets are of this sub-family, including BrachypelmaBrachypelmaBrachypelma is a genus of the family Theraphosidae containing various species of tarantulas.-Characteristics:The species are native to parts of Central America. Habitat destruction and pet-trade collection has led these spiders to be among the few arthropods protected under the international CITES...
, a genus of tropical new-world species generally considered docile and good starter species by those who keep tarantulas as pets.
- Thrigmopoeinae are Indian tarantulas.
A few genera are presently not well classified, and/or have classifications which are disputed, including Brachionopus, Cardiopelma, and Proshapalopus
Fossil record
Although there are fossils of mygalomorph spiders going back to the TriassicTriassic
The Triassic is a geologic period and system that extends from about 250 to 200 Mya . As the first period of the Mesozoic Era, the Triassic follows the Permian and is followed by the Jurassic. Both the start and end of the Triassic are marked by major extinction events...
, only two specimens have been found so far which can be convincingly assigned to Theraphosidae. One is from Dominican Republic amber, the other from Chiapas (Mexican) amber. Both these ambers are quite young, being Miocene
Miocene
The Miocene is a geological epoch of the Neogene Period and extends from about . The Miocene was named by Sir Charles Lyell. Its name comes from the Greek words and and means "less recent" because it has 18% fewer modern sea invertebrates than the Pliocene. The Miocene follows the Oligocene...
in age or about 16 million years old.
See also
- List of Theraphosidae species
- Spider families
- Tarantula bites
- Tarantula hawkTarantula hawkA tarantula hawk is a spider wasp which hunts tarantulas as food for its larvae. Tarantula hawks belong to any of the many species in the genera Pepsis and Hemipepsis in the family Pompilidae ....
(waspWaspThe term wasp is typically defined as any insect of the order Hymenoptera and suborder Apocrita that is neither a bee nor an ant. Almost every pest insect species has at least one wasp species that preys upon it or parasitizes it, making wasps critically important in natural control of their...
that feeds on tarantulas)
External links
- Tarantulas US Forum
- Word of the Day: Tarantula and Tarantella, etymology and folklore
- http://www.acs.ucalgary.ca/~schultz/cn-master.htm#species
- Overview of Species Information for All Named Theraphosidae Divided by Subfamily
- Listing of all currently named Theraphosidae
- Care for commonly kept Tarantula Pets
- American Tarantula Society Headquarters
- Amazing Tarantulas
- Watch Tarantula (Theraphosidae) video clips from the BBC archive on Wildlife Finder
- Tarantula BG