Tarantulas comprise a group of large and often hairy spiders of the family Theraphosidae. As of August 2022[update], 1,040 species have been identified, with 156 genera. The term "tarantula" is usually used to describe members of the family Theraphosidae, although many other members of the same infraorder (Mygalomorphae) are commonly referred to as "tarantulas" or "false tarantulas". Some of the more common species have become popular in the exotic pet trade. Many New World species kept as pets have setae known as urticating hairs that can cause irritation to the skin, and in extreme cases, cause damage to the eyes.
Most species of North American tarantulas are brown. Elsewhere, species have been found that variously display cobalt blue (Cyriopagopus lividus), black with white stripes (Aphonopelma seemanni), yellow leg markings (Eupalaestrus campestratus), metallic blue legs with vibrant orange abdomen and green prosoma (Chromatopelma cyaneopubescens). Their natural habitats include savanna, grassland such as in the pampas, rainforest, desert, scrubland, mountains, and cloud forest. They are generally classed among the terrestrial types. They are burrowers that live in the ground.
Tarantulas can be confused with other members of the order Mygalomorphae, such as trapdoor spiders, funnel-web spiders and purseweb spiders. They can also be confused with some members of the order Araneomorphae such as the Lycosidae family. There are multiple ways to identify a tarantula. First the hairs: in the Americas most tarantulas have urticating hairs, though some, such as the Hemirrhagus genus, lack these. The hairs are usually more noticeable than with most other spiders. Another is the size, as tarantulas tend to be bigger, but this is again not a failproof way. They also don't use their webs for hunting, instead using them as building material or tripwire.
The spider originally bearing the name tarantula was Lycosa tarantula, a species of wolf spider native to Mediterranean Europe. The name is derived from the southern Italian town of Taranto. The term tarantula was subsequently applied to almost any large, unfamiliar species of ground-dwelling spider, in particular to the Mygalomorphae and especially the New World Theraphosidae. Compared to tarantulas, wolf spiders are not particularly large or hairy, and so among English speakers in particular, usage eventually shifted in favour of the Theraphosidae, even though they are not closely related to wolf spiders at all, being in a different infraorder.
The name tarantula is also incorrectly applied to other large-bodied spiders, including the purseweb spiders or atypical tarantulas, the funnel-webs (Dipluridae and Hexathelidae), and the dwarf tarantulas. These spiders are related to tarantulas (all being mygalomorphs) but fall into different families from them. Huntsman spiders of the family Sparassidae have also been termed tarantulas because of their large size, when, in fact, they are not related. Instead, huntsman spiders belong to the infraorder Araneomorphae.
Some genera of tarantulas hunt prey primarily in trees; others hunt on or near the ground. All tarantulas can produce silk; while arboreal species typically reside in a silken "tube tent", terrestrial species line their burrows with silk to stabilize the burrow wall and facilitate climbing up and down. Tarantulas mainly eat large insects and other arthropods such as centipedes, millipedes, and other spiders, using ambush as their primary method of prey capture. Armed with their massive, powerful chelicerae tipped with long, chitinous fangs, tarantulas are well-adapted to killing other large arthropods. The biggest tarantulas sometimes kill and consume small vertebrates such as lizards, mice, bats, birds, and small snakes.
The pedipalpi are two six-segmented appendages connected to the prosoma near the mouth and protruding on either side of both chelicerae. In most species of tarantulas, the pedipalpi contain sharp, jagged plates used to cut and crush food often called the coxae or maxillae. As with other spiders, the terminal portions of the pedipalpi of males function as part of their reproductive system. Male spiders spin a silken platform (sperm web) on the ground onto which they release semen from glands in their opisthosoma. 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.
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.
All types of tarantulas have two sets of book lungs (breathing organs); the first pair 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 is 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.
Despite their large size and fearsome appearance and reputation, tarantulas themselves are prey for many other animals. The most specialized of these predators are large members of the wasp family Pompilidae such as the wasp Hemipepsis ustulata. These wasps are called "tarantula hawks". The largest tarantula hawks, such as those in the genus Pepsis, 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 egg hatches into a larva and feeds on the spider's inessential parts, and as it approaches pupation, it consumes the remainder. Other arthropods, such as large scorpions and giant centipedes, are also known to prey on tarantulas.
Tarantulas are also preyed upon by a wide variety of vertebrates. Many of these, including lizards, frogs, birds, snakes and mammals, are generalist predators of all kinds of large arthropods. Mammals that have been known to prey on tarantulas, such as the coati, kinkajou, and opossum in the New World, and mongooses and the honey badger in the Old World, are often immune to the venom of their arthropod prey.
Humans also consume tarantulas for food in their native ranges. They are considered a delicacy in certain cultures (e.g. Venezuela and Cambodia). They can be roasted over an open fire to remove the bristles (described further below) and then eaten.
Tarantulas have evolved specialized bristles, or setae, to defend themselves against predators. Besides the normal bristles covering the body, some tarantulas also have a dense covering of irritating bristles called urticating hairs, on the opisthosoma, that they sometimes use as protection against enemies. These bristles are present on most New World species, but not on any specimens from the Old World. Urticating hairs are usually kicked off the abdomen by the tarantula, but some may simply rub the abdomen against the target, like the genus Avicularia. These fine bristles are barbed and serve to irritate. They can be lethal to small animals such as rodents. Some people are sensitive to these bristles, 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 bristles off; they are flicked into the air at a target using their back pairs of legs. Tarantulas also use these bristles 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 molt. The intensity, number, and flotation of the bristles depends on the species of tarantula.
All tarantulas are venomous. Although their venom is not deadly to humans, some bites cause serious discomfort that might persist for several days. 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 of the African tarantula Pelinobius muticus also causes strong hallucinations.[need quotation to verify][additional citation(s) needed] For Poecilotheria species, researchers have described more than 20 bites with the delayed onset of severe and diffuse muscle cramps, lasting for several days, that in most cases resolved completely with the use of benzodiazepines and magnesium. In all cases, seeking medical aid is advised. 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. Additionally, the large fangs of a tarantula can inflict painful puncture wounds, which can lead to secondary bacterial infections if not properly treated. 2b1af7f3a8