Pet Goliath Bird Eating Spider

People usually look up the Goliath birdeater because they’re weighing up whether it’s a sensible pet: how big it really gets, what its bite and hairs can do, and what “rainforest conditions” actually mean in a home enclosure. Getting those basics wrong doesn’t just risk a nasty rash or a painful bite — it can also mean a stressed spider, failed moults, and avoidable losses.

Below is a practical, reality-checked guide to Theraphosa blondi (the Goliath birdeater): size and lifespan, temperament, housing and feeding, handling risk, and the small set of health problems keepers most often run into — with claims corrected where the original text was overstated or muddled.^{1, 2, 3}

Quick facts

• Scientific name: Theraphosa blondi¹
• Adult size: commonly up to ~30 cm leg span in large individuals; record-style measurements are often around the high 20s cm^{2, 3}
• Adult weight: up to ~170–175 g in very large specimens^{2, 3}
• Lifespan: females often around 20 years; males commonly 3–6 years^{1, 3}
• Range: northern South America (Amazon/Guiana Shield region)⁴
• Typical activity: mostly nocturnal, ground-dwelling, burrow-associated^{2, 4}

What “Goliath bird-eating spider” actually means

The name is sticky, but a little misleading. T. blondi is certainly capable of taking small vertebrates, and there are records of it eating birds, but most of its meals are invertebrates — with frogs, rodents and similar prey taken opportunistically when the chance arrives.^{1, 4}

In the wild it’s a stealthy, heavy-bodied hunter of the forest floor, more likely to be found near a burrow than out on open display.^{2, 4}

Size and appearance

This is one of the largest spiders people will ever see in real life. By mass, it’s widely regarded as the heaviest spider on Earth, with very large individuals reaching roughly 170–175 g. Leg span is commonly quoted up to around 30 cm, though truly exceptional measurements are often in the high 20s cm range in documented records.^{2, 3, 4}

Colour varies with the individual and lighting, generally brown to reddish-brown, with dense hairs (setae) that give it a velvety, bristled look. Those hairs aren’t decoration — some of them are part of its defence.

Temperament and defence (bite, hairs, “hissing”)

Goliath birdeaters are not social animals. In captivity they’re best treated as a display species: fascinating to observe, but not suited to handling. When threatened, a tarantula may stand its ground, rear up, and show fangs as a warning — and if the warning is ignored, it can bite.⁵

They also have other defences:

• Urticating hairs: like many New World tarantulas, they can kick barbed hairs from the abdomen. These can irritate skin and are especially troublesome if they get into the eyes or are inhaled.⁶
• Stridulation (“hissing”): some tarantulas can produce a rasping, hiss-like sound by rubbing body parts together (stridulation). It’s a warning signal, not a sign of friendliness.⁴

Venom is used to subdue prey, but for humans the bigger issues are often the mechanical injury from large fangs, the pain of the bite, and secondary effects like nausea in some cases. Any bite should be taken seriously, particularly if symptoms worsen or an allergic reaction is suspected.⁵

Housing: building a safe “rainforest floor” enclosure

T. blondi is a terrestrial burrower. In captivity, floor space, deep substrate, and stable humidity matter more than height or climbing features. The aim is a quiet, darkened forest-floor corner: damp but not swampy, with room to dig and a secure retreat.

Enclosure basics

• Secure lid: essential. Not because they’re fast like huntsman spiders, but because any escape in a home is a safety risk for both spider and people.
• Floor space: prioritise a wide enclosure that allows turning and walking without constant wall contact.
• Substrate depth: deep enough to burrow and hold shape; keep it slightly moist in the lower layers rather than wet on top.
• Hide: cork bark, a half-log, or a starter burrow encourages calm, stable behaviour.
• Water dish: always available. Hydration should not rely on misting alone.⁶

Temperature and humidity (practical, not perfectionist)

Most keepers aim for warm, stable conditions and moderate-to-high humidity, with good ventilation to avoid stagnant air. Overheating and constantly wet substrate are common beginner errors: they raise stress and can encourage mould and bacterial growth. If supplemental heat is used, it’s generally safer to warm the room or use an external heat source rather than heating the substrate from underneath, which can drive a spider to burrow into the hottest zone.⁷

Feeding: what to offer, and what to avoid

Despite the legend, most routine feeding in captivity is straightforward: appropriately sized invertebrates. Large roaches, crickets and similar prey are common staples. Vertebrate prey is not necessary for routine care and can introduce extra risk (injury to the spider, hygiene problems, and ethical concerns).^{1, 4}

A simple rule holds up well: don’t offer prey larger than the spider can safely overpower, and remove uneaten prey — especially around moulting time. Feeder insects should be well cared for (clean, well-fed) so they’re nutritionally worthwhile.

The original text recommended calcium supplementation for the spider; that advice is often misapplied. In practice, nutrition is better improved by gut-loading feeders and keeping prey varied, rather than dusting prey as if the spider were a reptile.

Handling: when “docile” still isn’t safe

Even a calm tarantula can defend itself suddenly, and a fall from hand height can be fatal to a heavy-bodied terrestrial species. For keepers, the risk isn’t only venom: it’s fangs, urticating hairs, and accidents during enclosure maintenance.^{5, 6}

If you need to move the spider (rehousing, deep clean, emergency):

• Use a catch cup/tub and a soft tool (paintbrush) to guide, not grab.
• Work low to the ground, in a clear area.
• Consider eye protection and gloves if you react to hairs or you’re working in a confined space.⁶

Common health problems (and what usually causes them)

Moulting trouble (the big one)

Moulting is normal, but it’s a vulnerable period. Dehydration, disturbance, or feeder insects left in the enclosure can turn a routine moult into a crisis. A spider preparing to moult may refuse food and become reclusive; during the moult itself, it should not be handled or “helped”. The best prevention is steady humidity, constant access to water, and removing live prey if the spider stops feeding.⁶

Dehydration

A dehydrated tarantula may appear weak, unsteady, or unusually curled. The fix is usually simple husbandry: accessible water and substrate moisture management, not constant misting of the animal.

Mould, mites, and “dirty enclosure” issues

Warmth and humidity speed up decay. Remove food leftovers promptly, keep ventilation adequate, and avoid waterlogged substrate. Clean, stable conditions reduce the odds of secondary infections and pest build-up.

Breeding and reproduction: reality check

Breeding T. blondi is not a casual project. It requires mature, correctly sexed animals, careful timing, and contingency plans for separation and rehousing. Egg sac size varies, and sweeping claims like “up to 500 eggs” aren’t reliable as a general expectation. Many sources instead describe clutches in the low hundreds for large tarantulas, with variation depending on the female and conditions.⁴

Conservation status and legality

The original text stated this species is listed as “Least Concern” by the IUCN. That is often repeated online, but it isn’t correct: reputable references note that the species has not been assessed by the IUCN Red List.⁴

Legality is location-dependent. Some places restrict tarantula keeping or importation, and Australia’s rules can be particularly strict around exotic species and biosecurity. Always check your local and state regulations before buying, selling, or importing any invertebrate.

Final thoughts

A Goliath birdeater can be an extraordinary animal to keep — not because it wants attention, but because it doesn’t. Most of the time it’s a patient presence: a living weight in the substrate, a careful rearrangement of a burrow entrance, the sudden stillness of a nocturnal hunter deciding whether tonight is the night to feed.

If you keep one, keep it on its own, keep it warm and steady, keep water available, and keep your hands out of the enclosure unless there’s a real reason to go in. That’s usually where both keeper and spider do best.^{5, 6}

References

1. National Geographic — Goliath birdeater facts
2. Guinness World Records — Largest spider (Theraphosa blondi)
3. Natural History Museum (UK) — What is the biggest spider?
4. Encyclopaedia Britannica — Goliath birdeater (Theraphosa blondi)
5. Australian Museum — Australian tarantulas (bite risk and handling cautions)
6. Animal Learning — Tarantula care overview (handling risks, moulting guidance, humidity cautions)
7. RSPCA — Advice on keeping invertebrates as pets
8. National Geographic — World’s biggest spider explained