About Brachypelma smithi (F.O.Pickard-Cambridge, 1897)
Brachypelma smithi is a large species of spider. In a sample of seven females, total body length (excluding chelicerae and spinnerets) ranged from 52–59 mm (2.0–2.3 in). A sample of eight males was slightly smaller, with total body length ranging 44–49 mm (1.7–1.9 in). While males have slightly shorter bodies than females, they have longer legs overall. The fourth leg is the longest: it measures 70 mm (2.8 in) in the type male and 66 mm (2.6 in) in a female. The legs and palps are bluish black, marked with three distinct colored rings: dark reddish orange on the portion of the patellae closest to the body, with light yellowish pink further away, pale yellowish pink on the lower part of the tibiae, and pinkish white at the end of the metatarsi. Adult males have a yellowish brown carapace, and the upper surface of their abdomen is black. Adult females show more variation in carapace color and pattern. Their carapace may be mainly bluish black with a light brown border; the dark area may also break up into a "starburst" pattern, or be almost reduced to two dark patches in the eye area. Brachypelma smithi and the very similar Brachypelma hamorii are found along Mexico's Pacific coast, on opposite sides of the Balsas River basin where it opens onto the Pacific. B. smithi occurs to the south, in the Mexican state of Guerrero. Its natural habitat is hilly deciduous tropical forest. Individuals construct or extend burrows under rocks and tree roots, within dense thickets and deciduous forests. The 1999 published description of these burrows did not distinguish between B. hamorii and B. smithi. Deep burrows protect B. smithi from predators such as the white-nosed coati, and allow the spiders to ambush passing prey including large insects, frogs and mice. Females spend most of their lives inside their burrows. Burrows are typically located in or not far from vegetation, and feature a single entrance connected to a tunnel that leads to one or two chambers. The entrance is only slightly larger than the spider's body size. The tunnel, usually around three times the tarantula's leg span in length, leads to a chamber large enough for the spider to molt safely. A larger chamber, where the spider rests and eats its prey, is located further down the burrow via a shorter tunnel. When the tarantula needs seclusion, for example while molting or laying eggs, it seals the entrance with silk, sometimes mixed with soil and leaves.
