Tarantula

Tarantulas make up the family Theraphosidae, a group of more than a thousand species found on every continent except Antarctica. They range from the fossorial Aphonopelma species of the American Southwest and Mexico to the tree-dwelling, brightly patterned Poecilotheria of South Asia and the robust baboon spiders of Africa. Despite their intimidating size, most species are slow-moving and rely on stealth and patience rather than speed or aggression to capture food.

What sets tarantulas apart from most other spiders is their remarkable longevity. Females of many species live fifteen to twenty-five years or more, continuing to molt periodically throughout adulthood, while males mature faster and live only a fraction as long. This life-history difference, combined with their calm temperament and striking appearance, has made tarantulas one of the most recognizable groups of spiders and a long-standing staple of the exotic pet trade.

Ecologically, tarantulas are important nocturnal predators of insects and other invertebrates in the habitats where they occur, and in turn they serve as prey for birds, mammals, and specialized predators such as tarantula hawk wasps, which paralyze them to provision their own larvae.

• Large, robust body covered in dense hair-like setae, ranging from earthy browns and blacks to metallic blues, purples, and orange-banded legs depending on species
• Eight eyes clustered tightly together on a small raised area at the front of the head, giving relatively poor eyesight compared to their sense of touch
• Fangs (chelicerae) that move up and down in a stabbing motion rather than pinching sideways, a trait shared by all mygalomorph spiders
• Thick, muscular legs covered in sensory hairs used to detect ground vibrations
• New World species often have a dense patch of urticating hairs on the top of the abdomen used defensively
• Lookalikes include wolf spiders and fishing spiders, which are considerably smaller, less hairy, and lack the tarantula's heavy-bodied build

Tarantulas occupy an enormous range of environments, from arid deserts and scrubland to humid tropical rainforest canopy. Ground-dwelling species dig their own burrows in soil or sand, or take over abandoned rodent holes, lining the entrance with silk to help detect vibrations from approaching prey. Arboreal species instead build silk retreats in tree bark crevices, hollows, or dense foliage. They are found across the Americas, Africa, southern Europe, and much of Asia and Australia, generally in warm temperate to tropical climates.

Tarantulas are ambush predators that spend the vast majority of their time motionless at or near their burrow entrance, relying on vibration-sensing hairs to detect passing insects, other arthropods, and, in the case of larger species, occasionally small lizards or amphibians. They are almost entirely nocturnal, emerging after dark to hunt or, in males, to wander in search of mates during the breeding season. When threatened, a tarantula may rear up on its hind legs in a defensive posture, flick urticating hairs toward the threat, or simply retreat into its burrow. As a group, tarantulas play a meaningful role in controlling insect and small invertebrate populations within their ecosystems.

A female tarantula produces a silk egg sac containing anywhere from fifty to several hundred eggs, which she guards closely until the spiderlings hatch and disperse to establish their own burrows. Tarantulas grow through a long series of molts, shedding their exoskeleton repeatedly over several years as they mature. Females continue to molt periodically even after reaching adulthood, contributing to their exceptional lifespans, while males stop molting once mature, actively seek out females during a single breeding season, and typically die within months to a year of maturing.