Brazilian White Knee

The Brazilian White Knee (Acanthoscurria geniculata) is one of the most striking large terrestrials in the hobby — velvet black legs banded with brilliant white 'knees,' a red-tinged abdomen, and a personality to match. Fast-growing (near 4" in a year), a voracious, dramatic feeder, and almost always out on display, it's a bold, robust Brazilian rainforest species that gives beginner-friendly care in a big, showy package. One of the best value 'wow' spiders you can keep.

Temperature75–82°F (24–28°C) — warm room; no heat lamp needed in most homes. Warmth drives its fast growth and huge appetite.
HumidityModerate to damp, 70–80%, with a lightly damp lower layer and a water dish. A rainforest species that likes some moisture — keep the base slightly moist and the surface drier, with ventilation. Don't waterlog it; damp base plus airflow.
Adult sizeA large tarantula: adults reach 7–8 inches across the legs (diagonal leg span). A relatively fast grower — expect visible progress between molts when well fed.
LifespanFemales roughly 12–20 years; mature males 4–7 years. Long-lived for a fast grower.

Enclosure

A large terrestrial footprint — floor space over height, substrate filled to keep falls short. A cork hide, a good water dish, cross-ventilation. It's an active, bold spider that's out on display rather than hiding, so give it a proper adult enclosure to roam.

Substrate & water

4+ inches of coco fibre/topsoil, lightly damp below and drier on top, with a water dish. It digs some but mostly roams and displays. Ventilate the damper base.

Feeding

A spectacular feeder — the feeding response is a real draw, hitting prey with startling force. Prey to abdomen size; juveniles twice weekly to fuel its fast growth, adults one item weekly. Bold and eager, rarely refusing outside premolt. Remove uneaten prey in 24 hours.

Temperament & defenses

Beginner-friendly but bold — confident and out in the open rather than defensive, though it will flick Type I/III urticating hairs when disturbed and isn't shy about standing its ground. Venom mild. Wash up after enclosure work; a hands-off display species given its size and hair-kicking.

Keeper’s notes

One of our favourite recommendations for a first big, showy spider — it grows fast, eats dramatically, wears that unmistakable white-banded look, and stays out where you can enjoy it. Hardy and forgiving apart from respecting the size and hairs. Bold personality, brilliant display, great value. A crowd-pleaser every time.