Tarantula Spider Facts, Identification & Control
Tarantulas (Theraphosa apophysis) are the largest known arachnids. On average, they measure 7 to 10 cm in length. However, they are capable of exceeding 30 cm. Tarantulas occur in a variety of colors, sizes and habitats. Many are black or brown in color and have hairy bodies. Tarantula species are distinguishable from other spiders by the dense body hair. Several species also bear distinct stripes along their legs. The perceived size of specimens is oftentimes exaggerated, due to the tarantula’s abundant hair. This hair, which covers the entire body of the tarantula, serves as a defense mechanism against predators. Although frightening in appearance, tarantulas are only aggressive when provoked.
Tarantula Anatomy / Body Parts
Tarantulas have strong exteriors known as exoskeletons. The tarantula’s body is comprised of two major parts: the prosoma, also known as the cephalothorax, and the abdomen, or opisthosoma. These two parts are joined by a pedicle, or pregenital somite, which is perceived to be the waist of the tarantula’s body. This pedicle is crucial to the mobility and agility of the tarantula, as it allows the opisthosoma a larger range of movement.
The eight legs, pedipalps and fangs of the tarantula are also connected to the tarantula’s body at the prosoma. The chelicerae, or fangs, which release venom, are located below the tarantula’s eyes. The legs of the tarantula are seven-segmented and feature retractable claws, which are used for climbing. Hairs present on the legs are also useful in climbing upright or slippery surfaces.
Behavior, Diet & Habits
The diet of the tarantula includes grasshoppers, beetles and other spiders. Vertebrates such as mice, toads, snakes, frogs and lizards may also fall prey to the tarantula depending on the species. Arboreal species prey upon flying insects, moths and frogs. Although they do have silk-producing capabilities, most tarantulas do not weave aerial webs to trap their prey. Rather, they utilize ambush strategies or hunt for food at night. Depending on the species, most tarantulas hide within their burrows to ambush prey as it walks by or may wander nearby to the burrow looking for a meal. Tarantulas move quickly for short bursts and inject their prey with venom in order to paralyze it. This venom is toxic to small animals but is not known to be life-threatening for the average human adult.
Tarantulas typically live in arid, semidesert regions and in tropical rainforests. As their common name implies, desert tarantulas are also found in arid habitats. Some tarantulas are arboreal and spin silken retreats in tree holes, while others are terrestrial and dwell in burrows.
Do Tarantulas Spin Webs?
Tarantulas are capable of producing silk and can use it for similar purposes, depending on species. Many of the arboreal tarantulas make silken homes in tree holes or other crevices. Even the burrowing terrestrial species use silk to line their burrows, and some use silk to create door-like entrances to their burrows. The tarantula’s silk acts as an alarm system, alerting the arachnid to the presence of threat or prey outside its home. If the intruder is potential prey, the tarantula will capture and subdue it.
All tarantulas undergo molting, during which they shed their exoskeletons in order to grow. Tarantulas undergo a series of such molts at various developmental stages. Read more about the molting process.
Some tarantula specimens have been known to live for many years.
Life Cycle/ Reproduction
The life cycle of the tarantula depends on the species. The life cycle begins with the mating process, during which males leave their territories in search of mates. Male tarantulas are known to travel great distances in order to locate females (which leads people to think they are migrating). Unfortunately, their wanderings may lead them into contact with people, such as on roadways or in people’s homes.
Males usually spin a sperm web onto which they deposit sperm. They draw the sperm into their pedipalps. Once they locate a female they test her receptiveness by tapping near her burrow or web. After performing a specialized courting ritual, males fertilize females and then move on quickly, as females are sometimes known to devour their mates following sexual contact. However, males that resist consumption rarely survive more than a few months following copulation.
Females deposit their eggs into cocoon-like structures known as eggs sacs. These eggs incubate for a period of time and hatch into young tarantulas, which molt several times as they grow. Molting continues throughout the life of the female tarantula. Males usually cannot successfully molt after they become mature. The intervals between molts grow longer as tarantulas mature. Male tarantulas typically do not live as long as females, with the female of some species living up to 35 years.
Tarantulas belong to Kingdom Animalia, Phylum Arthropoda, Class Arachnida, Order Araneae and Family Theraphosidae. Five genera and 30 species of tarantulas have been documented in the United States, each with its own scientific name. There are over 800 documented tarantula species in the world.
In the United States, the most common type of tarantula is the Eurypelma californicum. This species can be found in the desert areas of California, Texas and Arizona. Another common North American species is the Aphonopelma chalcodes, or desert tarantula. Desert blond tarantulas are also present on the continent and dwell primarily in Arizona and other arid locations. Desert tarantulas can grow up to 7.5 cm in length and range in color from gray to dark brown.
Tarantulas can be found in Kansas. Some tarantulas in Kansas reside in rocky habitats, while others reside in hillsides. Most burrow underground. Texas brown tarantulas (Aphonopelma hentzi) are definite inhabitants of this area. Researchers also believe that the Texas brown tarantula may be present in the southern third of the state.
Although tarantulas are not native to Florida, several species have been introduced due to pet trade and importation. The most recognized tarantula in Florida is the Brachypelma vagans. Originally of Mexican origin, these tarantulas are believed to have entered Florida in the 1980s, although official identification did not occur until 1998. Also commonly known as Mexican red rumps, these arachnids are black with red abdomens. While painful, their bites are not fatal to humans.
Mexican fire legs, Mexican red legs and Mexican pinks are all terrestrial tarantulas, slow moving and indigenous to Mexico.
The Togo starburst tarantula and the sunburst baboon tarantula are found on the African continent. Costa Rica is home to the zebra leg tarantula, also known as the white knee tarantula. These tarantulas are named for their conspicuous leg markings.
Tarantula Form of Protection
Although tarantulas are formidable predators, they also serve as prey to other creatures. The tarantula hawk wasp is one of these and utilizes the bodies of tarantulas as egg incubation sites. Other predators such as mammals, birds and reptiles attack tarantulas for food. As a result, the tarantula has developed a series of protective mechanisms.
New World tarantulas’ bodies often have defensive hair. These hairs, known as urticating hairs, cause severe irritation after coming into contact with the skin of an attacker. As the predator attempts to relieve itself of this irritation, tarantulas are given time to run and hide. The tarantula also can fling the hairs into the air by briskly rubbing their abdomens with their hind legs.
When handled, some tarantulas release urticating hairs that can cause itchiness and discomfort. Some species are capable of launching these hairs at predators with their back legs.
The natural enemies of tarantulas are varied and include other arachnids, such as scorpions. Because both tarantulas and scorpions reside in desert habitats, they may come into contact with one another. While both are equipped with specialized defense mechanisms, scorpions might overcome tarantulas with their more powerful venom and claws.
The tarantula hawk, a large wasp, is one of the tarantula’s deadliest enemies. Some are metallic blue to green with reddish orange wings. The tarantula hawk uses its venom to paralyze the tarantula. The wasp then drags the tarantula back to its lair, where its immobilized body is used as an incubation site for their eggs. When the eggs hatch, they consume the tarantula’s still living body.