The Goliath birdeater (Theraphosa blondi) belongs to the tarantula family Theraphosidae. Found in northern South America, it is the largest spider in the world by mass () and body length (up to ), and second to the giant huntsman spider by leg span. It is also called the Goliath tarantula or Goliath bird-eating spider; the practice of calling theraphosids "bird-eating" derives from an early 18th-century copper engraving by Maria Sibylla Merian that shows one eating a hummingbird. Despite the spider's name, it rarely preys on birds. Physical description These spiders can have a leg span up to , a body length of up to and can weigh up to . Birdeaters are one of the few tarantula species that lack tibial spurs, located on the first pair of legs of most adult males. They are mostly tan to light brown and golden-hued. Lifecycle Unlike other species of spider/tarantula, females do not eat the males during mating. Females mature in 3–6 years and have an average lifespan 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. Bird-eaters have hair on their bodies, abdomens, and legs. The female lays 100 to 200 eggs, which hatch into spiderlings within 6–8 weeks. Behaviour Defenses In response to threats, Goliath birdeaters stridulate by rubbing setae on their pedipalps and legs. Also, when threatened they rub their abdomen with their hind legs and release hairs that are a severe irritant to the skin and mucous membranes. These urticating hairs can be harmful to humans. Like all tarantulas, T. blondi spiders have fangs large enough () to break the skin of a human. 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. Tarantulas generally bite humans only in self-defence, and these bites do not always result in envenomation (known as a "dry bite”). Feeding Despite its name, the Goliath birdeater only rarely actually preys on birds; in the wild, its diet consists primarily of other large arthropods, worms, and amphibians. However, because of its size and opportunistic predatory behavior, this species commonly kills and consumes a variety of insects and small terrestrial vertebrates. They do not consume their prey in the open;