Goliath Birdeater: A Huge Tarantula That Only Eats Birds Sometimes

In the dense rainforests of northeastern South America, a giant lurks beneath banana leaves and within deep burrows. Meet the goliath birdeater, the largest tarantula species on Earth. This spider is so big, it can span the size of a dinner plate, making it the undisputed heavyweight of the arachnid world.

Despite its name, the goliath bird eating spider rarely preys on birds. Its diet consists primarily of insects, small terrestrial animals, frogs and the occasional rodent or snake. And yes, while it's been observed feeding on birds, this is more the exception than the rule.

Size and Appearance

The goliath birdeater (Theraphosa blondi) can have a leg span of up to 11 inches (28 centimeters) and a body length of approximately 4.75 inches (13 centimeters). These spiders are covered in light brown to golden-hued hairs with faint markings across their legs and abdomen.

Adult females are much larger and longer-lived than adult males. While males die shortly after reaching sexual maturity, females can live up to 20 years in captivity.

Habitat and Behavior

Native to the upland regions of northern South America — including northern Brazil, French Guiana and parts of Venezuela — the goliath birdeater prefers humid, swampy forests. It creates deep burrows or takes shelter under rocks and logs.

This is a nocturnal species with opportunistic predatory behavior. It waits in ambush, using its keen sense of vibration to detect prey. While they do have eight eyes, their vision is poor.

Defense Mechanisms

When threatened, the goliath birdeater doesn't rely solely on its fangs. One of its primary defenses includes rubbing bristles on its hind legs to release urticating hairs — tiny barbed irritants that act as a severe irritant to predators.

It may also rear up and display its large fangs, which are capable of delivering a venomous bite. Although tarantulas generally bite humans only when provoked, the goliath birdeater's venom is not lethal but can cause swelling and pain. The toxin found in its bite is designed more for paralyzing small prey than harming large animals.

Feeding and Digestion

spider with dead mouse — To be fair, we get really excited about dinner too. Milan Zygmunt / Shutterstock

The goliath birdeater's powerful fangs inject venom that helps liquefy its prey, initiating the digesting process externally. The spider then sucks up the resulting nutrient-rich slurry.

Captive adult female feeding behavior has shown they consume insects, amphibians, small vertebrates and even shrimp-like crustaceans.

Reproduction and Lifespan

Females mature in about three to five years and can produce hundreds of eggs at once, which they guard vigilantly. Most adult males, however, have a much shorter lifespan, dying soon after mating.

Unlike most other species, the goliath birdeater lacks tibial spurs on its legs, which male tarantulas typically use to hold the female during mating.

Scientific and Cultural Interest

The spider family Theraphosidae, which includes the goliath birdeater, intrigues both scientists and hobbyists. The British Tarantula Society and arachnologists studying spider ecophysiology have detailed its unique adaptations, while institutions like National Geographic and the media related to large spiders continue to showcase its awe-inspiring presence.

This species is a key part of its ecosystem, helping control populations of smaller animals. Its conservation status is not fully understood, but habitat destruction in South America poses a potential threat.

We created this article in conjunction with AI technology, then made sure it was fact-checked and edited by a HowStuffWorks editor.