The Goliath Bird-eater Spider (also called the Goliath Birdeater) (Theraphosa blondi) is an arachnid belonging to the tarantula group, Theraphosidae, and is considered to be the largest spider (by leg-span) in the world. The spider was named by explorers from the Victorian era, who witnessed one eating a hummingbird.
It is native to the rain forest regions of northern South America. These spiders have up to a 11 inch (25 cm) leg span and can weigh over 6 ounces (170 g). Wild Goliath birdeaters are a deep-burrowing species, found commonly in marshy or swampy areas, usually living in burrows that they have dug or which have been abandoned by other burrowing creatures.
Females always mate, but eventually kill their mates. Females mature in 3 to 4 years and have an average life span of 15 to 25 years. Males die soon after maturity and have a lifespan of three to six years. Colors range from dark to light brown with faint markings on the legs. Birdeaters have hair on their bodies, abdomens, and legs. The female lays anywhere from 100 to 200 eggs, which hatch into spiderlings within two months.
Birdeaters are one of the few tarantula species which lack tibial spurs, located on the first pair of legs of most adult males, which serve to keep the fangs of the female immobilized during mating, so that the female doesn't eat the male.
The Goliath birdeater is fairly harmless to humans, as are most species of tarantulas. Like all tarantulas, they have fangs large enough to break the skin of a human (.75 to 1.5 inches or 1.9 cm to 3.8 cm). They carry venom in their fangs and have been known to bite when threatened, but the venom is relatively harmless and its effects are comparable to those of a wasp's sting.
Also when threatened they rub their abdomen with their hind legs and release hairs that are a severe irritant to the skin and mucus membranes. Tarantulas generally bite humans only in self-defense, and these bites do not always result in envenomation (known as a "dry bite"). The Goliath birdeater has poor eyesight and mainly relies on vibrations in the ground that it can sense from its burrow.
Birdeaters are defensive and may make a hissing noise when disturbed. This noise is called stridulation and is produced when the spider rubs the bristles on its legs together. Birdeaters can defend themselves by biting or by kicking urticating hair towards their perceived assailant. These hairs can be severely irritating to the skin and lungs, and have been reported to feel like shards of fiberglass. While feeding, the spider will turn and leave a web barrier to prevent interruption from other animals.
Despite its name, the Goliath Birdeater does not normally eat birds. As with other species of spider, (specifically tarantulae), their diet consists primarily of insects and other invertebrates. However, because of its naturally large size, it is not uncommon for this species to kill and consume a variety of vertebrates. In the wild, larger species of tarantula have been seen feeding on rodents, lizards, bats and even deadly venomous snakes.
In captivity, the Goliath Birdeater's staple diet should consist of cockroaches (generally the Madagascar hissing cockroach, Gromphadorhina portentosa), anoles, and an occasional small mouse. Spiderlings and juveniles can be fed crickets or cockroaches that do not exceed the body length of the individual.