Mexican Red Knee Tarantula
Brachypelma hamorii
Theraphosidae (Tarantulas), Order Araneae. Key characteristics include large size, dense hair, and two pairs of book lungs.
Physical Description
A heavy-bodied, hirsute spider. It features a broad cephalothorax and a bulbous abdomen. Both the body and legs are covered in dense sensory hairs (setae) and urticating hairs used for defense.
Size Estimate
Adult females reach a body length of 2.5-3 inches with a leg span of 5-6 inches. Males are slightly smaller with longer, thinner legs.
Coloration & Markings
Primarily black or dark brown body with striking orange-red 'knees' on the patella. The carapace is tan/golden with a dark central triangle, and the abdomen is black with long reddish hairs.
Web Type
Terrestrial burrower; does not spin an aerial web. It uses silk to line the interior of its burrow for structural integrity and to sense vibrations from approaching prey.
Eye Arrangement
A small ocular tubercle on the front-center of the carapace containing eight small eyes arranged in two rows. Despite having eight eyes, their vision is very poor, primarily limited to light and dark.
Leg Characteristics
Thick, powerful legs designed for walking and digging. Each leg has a reddish-orange band on the patella. The tips of the legs have specialized tarsal claws and scopulae for climbing smooth surfaces.
Venom & Safety Information
Venom Information
Mildly venomous; the venom is designed to immobilize small prey. It is not considered medically significant to humans, often compared to the intensity of a bee sting.
Medical Significance
Low danger level. Initial symptoms of a bite include localized pain and swelling. The urticating hairs, however, can cause severe irritation, rashes, or respiratory distress if inhaled or if they enter the eyes.
Safety Recommendations
If encountered, do not disturb. If handling is necessary, use a soft brush to nudge it into a container. Avoid touching your face or eyes after being near one, as urticating hairs cause intense itching.
Habitat & Behavior
Habitat & Range
Endemic to the Pacific coast of Mexico, specifically in the states of Colima, Jalisco, and Michoacán. They prefer dry tropical scrub forests and arid thorn forests.
Behavior & Temperament
Very docile and slow-moving. They are nocturnal ambush hunters. When threatened, they are more likely to flee or flick urticating hairs from their abdomen than to bite.
Diet & Prey
Generalist carnivore. Diet consists of insects like crickets and roaches, but large adults may occasionally consume small lizards, frogs, or mice.
Seasonal Activity
Active year-round in their burrows, but sightings of males increase during the rainy season when they wander into the open to search for mates.
Description
The Mexican Red Knee is the 'poster child' of the tarantula world. Known for its steady temperament and vibrant orange-on-black aesthetic, it is a staple in both the pet trade and film industry. In the wild, it is a patient predator, spending most of its life in its silk-lined burrow.
Key Features
Black cephalothorax with golden border, bright orange-red highlights on the leg joints (patellae), and a black abdomen with sparse reddish hairs.
Similar Species
Brachypelma smithi (the 'original' Red Knee), which is nearly identical and was only scientifically split into two species recently. B. smithi typically has slightly brighter coloration.
Life Cycle
Extremely long-lived; females can live up to 25-30 years, while males live only 5-10 years. Mating involves complex drumming rituals. Females produce an egg sac containing 200-400 spiderlings.
Ecological Importance
As an apex invertebrate predator, they control insect populations. They also serve as a food source for larger predators like the Pepsis wasp (Tarantula Hawk) and some mammals.
Conservation Status
Listed as Near Threatened by the IUCN and protected by CITES to regulate international trade and prevent habitat loss from impacting wild populations.
Interesting Facts
The genus Brachypelma is protected under CITES Appendix II due to over-collection for the pet trade. They are also famous for being used in Hollywood movies because of their docile nature.
Photography Tips
A macro lens is ideal for capturing the texture of the setae. Use soft, diffused light to avoid glares from the packaging or the spider's carapace. Low-angle shots highlight the impressive leg span and orange knees.
Identified: 2026-07-06T02:17:36.636156