Brazilian Whiteknee Tarantula, Giant White Knee
Acanthoscurria geniculata
Theraphosidae (Tarantulas), Order Araneae
Physical Description
A large, heavy-bodied terrestrial tarantula. It features a dark, velvet-like carapace and a plump abdomen covered in reddish-brown urticating hairs. The body is densely hirsute (hairy) with a robust build characteristic of New World ground-dwellers.
Size Estimate
Estimated diagonal leg span of 4-6 inches in this specimen, likely a sub-adult. Adults can reach a massive 8-inch leg span.
Coloration & Markings
Black to deep brown base color. The most striking feature is the brilliant white bands at the joints (patella and tibia) of the legs. The abdomen features long, scattered reddish or orange-tinted hairs.
Web Type
Does not build an aerial capture web. It is a terrestrial wanderer and opportunistic burrower that uses silk to line its retreat and create 'alarm wires' on the ground.
Eye Arrangement
Small ocular tubercle on the anterior of the carapace containing eight eyes in a tight, compact cluster, typical of the Theraphosidae family.
Leg Characteristics
Thick, powerful legs designed for sprinting and pinning prey. Highly visible white banding at the joints and prominent scopulae (dense hair pads) on the feet for gripping surfaces.
Venom & Safety Information
Venom Information
Possesses a mild, digestive-enzyme based venom. It is not considered medically significant to humans, though the mechanical damage from large fangs can be painful.
Medical Significance
Low danger level. The primary medical concern is an allergic reaction to urticating hairs, which cause skin and eye irritation. Bites result in localized pain and swelling similar to a bee sting.
Safety Recommendations
Do not handle this species directly due to the risk of urticating hairs. If cleaning an enclosure, use long forceps. If 'haired,' wash the area with soap and water and avoid touching your eyes.
Habitat & Behavior
Habitat & Range
Native to the tropical rainforests of Northern Brazil. They prefer humid floor environments under fallen logs or in abandoned burrows.
Behavior & Temperament
Known for a high feeding response and being somewhat 'skittish.' While not typically aggressive, they are defensive and quick to flick urticating hairs from their abdomen if disturbed.
Diet & Prey
Generalist carnivore. Preys on insects like crickets and roaches, but large adults are capable of taking small lizards, frogs, and rodents via ambush.
Seasonal Activity
Active year-round in tropical climates, with activity peaks during the rainy season when mating typically occurs.
Description
The Brazilian Whiteknee is a crown jewel of the tarantula world, prized for its stark monochromatic leg bands and impressive size. It is a bold, terrestrial giant that spends much of its time out in the open rather than hidden in a burrow, making it a favorite for display.
Key Features
Bold white banding on the joints, dark black/brown cephalothorax, and red abdominal hairs.
Similar Species
Nhandu chromatus (Brazilian Red and White) which has a lighter carapace, and Acanthoscurria brocklehursti which has thinner white bands.
Life Cycle
Females can live up to 20 years, while males live 4-5 years. They reproduce via egg sacs that can contain 500-1000 spiderlings. Growth is rapid for a tarantula.
Ecological Importance
Acts as an apex invertebrate predator, controlling populations of large insects and small vertebrates in the Brazilian rainforest floor ecosystem.
Conservation Status
Not listed by IUCN, but threatened by habitat destruction in the Amazon basin and historical over-collection for the pet trade.
Interesting Facts
Despite their intimidating size, they are primarily defensive 'hair-kickers' rather than biters. They are one of the most popular large tarantulas in the exotic pet trade due to their fast growth rate.
Photography Tips
Focus on the white knee joints for identification. Use a medium-range macro lens to keep a safe distance, as they can kick hairs or lunge quickly when startled.
Identified: 2026-07-06T19:52:18.988887