Species Fact Profile: Mexican Red-Knee Tarantula (Brachypelma smithi)

Mexican Red-Knee Tarantula

Brachypelma smithi (F. O. Pickard-Cambridge, 1897)

Range: Mexico's Central Pacific Coast
Habitat: Desert, Scrub, Deciduous Forest
Diet: Insects, Small Vertebrates
Social Grouping: Solitary
Reproduction: Breed during the summer rainy season.  Male deposit sperm under female's abdomen using his small front limbs.  Hundreds of eggs laid in the spring in a mass of silk, with eggs hatching three months later.  Young spend a few weeks in the egg mass after hatching, then disperse from the burrow two weeks later.  Males mature at 4 years old, females at 6-7 years old
Lifespan: 5 Years (Males), 25 Years (Females)
Conservation Status: IUCN Near Threatened, CITES Appendix II

• Body length (excluding leg-span) ranges from 1.5-2.5 inches, with males smaller than females (though males tend to have longer legs)
• Dark brown body and legs with orange-red coloration at the leg joints
• In captivity, females are known to kill and consume the male shortly after mating.  It is uncertain if this occurs in the wild.
• Spend most of their lives in burrows, with entrances just large enough to allow the spider entry.  When vulnerable - molting, laying eggs - the spider may block up the entrance of the burrow with a combination of silk, soil, and leaves.
• Hunt at night from an ambush position, sensing the presence of the prey by feeling for vibrations.  Prey is held in the front limbs, then injected with venom, which paralyzes the prey and initiates digestion
• If threatened, will flick hairs off the abdomen, which can cause temporary blindness if they hit the eyes or rashes if they hit the skin.  Some predators, such as coatis, counter this by rubbing the fur off of the spider before consuming it
• One of the most commonly used spiders in movies due to its large size, striking coloration, and docile, tractable manner
• Scientific information about this species is somewhat jumbled, as historic reports (and even some contemporary scientific papers) confuse it with other Brachypelma species, some of which look fairly similar
• Historically one of the most popular pet tarantula species, collected by the thousands from the wild.  Now protected for trade by quota system, though smuggling still occurs.  Habitat loss is the new major threat