The Mexican Red Rump (Tliltocatl vagans, formerly Brachypelma vagans) is a popular terrestrial tarantula species native to Mexico and Central America. Known for its striking appearance—a velvety jet-black body contrasted by vibrant red hairs (setae) on its abdomen—it is widely favored in the pet trade as a hardy and relatively docile species for beginners. 
 
Key Biological Facts (2026)
Scientific Classification: Its genus was updated from Brachypelma to Tliltocatl in 2020, a change now fully accepted by major world spider catalogs.
Size: They can reach a leg span of 5–6.5 inches (13–16 cm). Females are typically larger and more robust than males.
Lifespan: Females are notably long-lived, reaching 25 to 40 years in some cases. Males have a much shorter life, typically living 5 to 8 years.
Defense Mechanisms: As a New World species, it possesses urticating hairs on its abdomen. When threatened, it kicks these barbed hairs, which can cause severe irritation to skin and eyes. While venomous, its bite is generally considered mild for humans, comparable to a bee sting.
Habitat: Naturally found in shrublands and tropical forests of Mexico and Guatemala, it is also established as a non-native species in parts of Florida following accidental or intentional releases in the 1990s. 
 
Care and Husbandry
Housing: Requires a terrestrial enclosure with deep substrate (4–5 inches) for burrowing. They are opportunistic burrowers and often stay near their hides.
Temperature & Humidity: Thrives in ambient temperatures of 68°F to 76°F (20°C to 24°C) with moderate humidity (65–75%). It is important to keep the bottom layers of substrate moist while letting the top dry out.
Diet: A voracious eater, it typically feeds on insects like crickets, roaches, and mealworms. Large adults may occasionally take small lizards or rodents. 
 
Cultural and Scientific Interest
Traditional Medicine: The Ch’ol Maya people in Mexico historically used the spider medicinally, crushing it to create a drink intended to treat "tarantula wind" (respiratory symptoms like asthma or chest pain).
Medical Research: A peptide in its venom, GsMtx-4, is actively being investigated for potential treatments for conditions such as cardiac arrhythmia, muscular dystrophy, and certain types of cancer.