Mexican redknee tarantula
The Brachypelma smithi (also called Mexican Red-kneed Tarantula), is a terrestrial tarantula native to the western faces of the Sierra Madre Occidental and Sierra Madre del Sur mountain ranges in Mexico. They are quite large, very docile and believed to be one of the most long-lived tarantulas.
The mature Brachypelma Smithi has a dark-colored body with orange patches on the joints of its legs, the second element of the legs (the trochanter) is orange-red. Following molting, the colors are more pronounced. The dark portion is very black while the orange-red portions will be far more on the reddish side.
An adult female has a body roughly 4 inches long, with a leg span of 6 inches, and a weight of approximately 15 grams. Both sexes are similar in appearance, with the male having a somewhat smaller body, but longer legs. Thus the male is of comparable size to the female, but weighing significantly less.
They grow very slowly and mature relatively late. Males can be expected to live for 10 to 15 years, while females can live considerably longer, somewhere between 20 and 40 years. This is uncertain as they have not been studied for long enough.
Like most New World tarantulas, they will kick urticating hairs from their abdomens if disturbed, rather than bite. They are not venomous to humans and are considered extremely docile, though, as with all Tarantulas, allergies may intensify any bite.
They carve deep burrows into soil banks, which keeps them protected from predators, like the White-nosed Coati, and enables them to ambush passing prey. The females will spend the majority of their lives in their burrows. The burrows are typically located in or not far from vegetation and consists of a single entrance with a tunnel leading to one or two chambers. The entrance is just slightly larger than the body size of the spider. The tunnel, usually about three times the tarantula's leg span in length, leads to a chamber which is large enough for the spider to safely molt in. Further down the burrow, via a shorter tunnel, a larger chamber is located where the spider will rest and eat its prey. When the tarantula needs privacy, e.g. when molting or laying eggs, the entrance is sealed with silk sometimes supplemented with soil and leaves.
Their natural habitat is in deciduous tropical forests in the hilly southwestern Mexico, especially in Colima and Guerrero. In 1985 the species were listed as endangered by CITES because the wild-caught specimens shipped for the pet market were decreasing in size. The smaller sizes were suspected to be a consequence of a declining population due to excessive export. The export is not the only threat however; some local people have reportedly made a habit of killing these spiders in a nearly systematic way using pesticides, pouring gasoline into burrows or simply killing migrating spiders on sight. The causes of these actions seem to be an irrational fear based on myth surrounding B. smithi and related species. Thus, whether the listing strengthened the B. smithi's wild population or not remains uncertain. The species has nonetheless been bred successfully in captivity, making them readily available on the pet market despite almost no export of wild-caught spiders from Mexico.
- ^ a b c d e f Stanley A. Schultz, Marguerite J. Schultz. The Tarantula Keeper's Guide: Comprehensive Information on Care, Housing, and Feeding (Revised Edition). Barrons (2009).
- ^ a b A. Locht, M. Yanez and I. Vazquez. Distribution and Natural History of Mexican Species of Brachypelma and Brachypelmides. Journal of Archeology (1999).
- ^ http://www.minaxtarantulas.se/articles/brachypelma-smithi-cambridge-1897/