The heaviest spider on Earth, a massive New World terrestrial tarantula from the South American rainforest floor. Spectacular but demanding, with potent urticating hairs and exacting humidity needs that make it a species for experienced keepers. Note that many spiders sold in the hobby as T. blondi are actually the very similar Theraphosa stirmi, which has near-identical care.
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The world's largest tarantula by mass (up to ~170 g); leg span up to ~11-12 in (28-30 cm) and body the size of a fist.
Lifespan
6–25 years
Social needs
solo
Native region
Northern South America (Guiana Shield rainforest: Guyana, Suriname, Venezuela, northern Brazil)
Origin
New World
Climate
🌴 Tropical
Family
Theraphosidae
Genus
Theraphosa
Part of the Tarantulas
Theraphosid spiders kept as low-maintenance display invertebrates. New World species are generally docile with mild venom but bear irritating urticating hairs, while Old World species lack those hairs but tend to be fast, defensive, and have more potent (though rarely life-threatening) venom.
From the minimum an animal needs to be kept humanely, up to the ideal setup. Bigger is almost always better — minimums are floors, not targets.
Photo coming soon
Minimum
Juvenile / sub-adult Goliath
12 × 12 × 10 in with 6 in damp substrate
Goliath birdeater (Theraphosa stirmi/blondi) is the world's largest spider by mass and grows fast — keep substrate damp (high humidity), a cork hide, and a big water dish.
Photo coming soon
Recommended
Adult Goliath enclosure
18 × 18 × 12 in with 8–10 in damp substrate
Adults need a wide, deep footprint with constantly damp packed soil so they can excavate a chamber. They kick severe urticating hairs — never house at face level.
Photo coming soon
Ideal
Walk-in giant fossorial vivarium
24 × 18 × 14 in bioactive, ~80% RH
Bioactive enclosure with tropical isopods, leaf litter, packed deep substrate, and a sculpted retreat. Sustained 75–85% humidity with cross-ventilation; this is one of the most demanding pet inverts.
Life & growth stages
How this animal changes through its life — each stage often has its own care, diet and space needs.
Photo coming soon
Egg
These invertebrates lay eggs — often in a guarded clutch, a silk sac (spiders), or a brood (carried by female isopods). The eggs are small and soft and develop without a true larval or pupal transformation.
Photo coming soon
Juvenile
Juveniles hatch as miniature versions of the adult and grow by molting their exoskeleton (or, in snails, by enlarging the shell). They gain size, segments, or leg pairs and gradually take on adult coloration with each molt.
Adult
Adults reach full size and reproductive maturity with the species' mature form and coloration. Many arachnids and myriapods continue to molt as adults, and sexes can differ in size or in specialized appendages.
Habitat & enclosure
House one spider alone in a large, moisture-retentive terrestrial enclosure (a 20-gallon-plus footprint for an adult) with deep substrate, ample floor space, and low height. Provide a large cork-bark hide and a big water dish. As a rainforest species it needs warmth and high humidity: 75-82F (24-28C) and roughly 80% humidity, maintained by keeping deeper substrate damp while ventilating well to avoid stagnation. No UVB required. Good cross-ventilation is critical to prevent mold and stagnant air in the humid setup, and true T. blondi is notoriously sensitive to drops in moisture.
Substrate
Use 5-8 in (12-20 cm) of a moisture-retentive coco-fiber/topsoil mix that holds humidity and allows burrowing. Keep lower layers damp and the surface a bit drier, and pair the moisture with strong ventilation. Spot-clean diligently, as the large prey items and humid conditions can foster mold and mites.
Equipment & setup
Provide thermostat-controlled supplemental heat only if the room is cool (side-mounted). No UVB. Essentials include a large, well-ventilated, moisture-retentive enclosure, a big hide, and a large water dish. Long feeding tongs, a catch cup, gloves, and eye protection are strongly recommended for safe maintenance of this large, hairy, defensive species. A hygrometer helps monitor its higher humidity needs.
Diet
A powerful predator with a large appetite; feed sizeable crickets, dubia roaches, and other appropriately sized feeders. Slings feed 2-3x weekly, juveniles weekly, adults every 1-2 weeks. Despite the name, it rarely eats birds in the wild and needs no vertebrate prey in captivity; a varied insect diet is best. Remove uneaten prey, withhold food in premolt, and keep water constantly available.
Behavior & temperament
A skittish, defensive New World giant. Its urticating hairs are among the most irritating of any tarantula and can cause severe skin, eye, and respiratory irritation; it also stridulates (hisses) audibly when threatened. Venom is mild, but the large fangs (up to ~2 cm) can deliver a mechanically painful, puncturing bite. It is strictly a display animal and should never be handled; even routine maintenance warrants caution and protection from its hairs.
Health
Less forgiving than smaller New World species, mainly due to its humidity requirements and sensitivity to dehydration and poor ventilation; true T. blondi in particular has a reputation for sudden death if moisture is allowed to drop. Keep deeper substrate damp but never let the enclosure go stagnant or moldy. Its heavy body makes falls especially dangerous, so keep the lid low. Its potent hairs warrant gloves and eye protection during maintenance. Never disturb a molting spider; a molt for an animal this size is a major, stressful event.
Tips, DIY & hacks
Balance high humidity with strong cross-ventilation; this is the single hardest part of its care and the main reason true T. blondi is considered demanding. Keep the enclosure low to prevent fatal falls, and always protect skin and eyes from its severe urticating hairs during maintenance. Treat it as a no-handling display centerpiece. If you want an easier introduction to the genus, captive-bred T. stirmi is hardier and more drought-tolerant.
