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 – 175 g (6.2 oz) – and body length – up to 13 cm (5.1 in) – but it is second to the giant huntsman spider by leg span. It is also called the 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 only rarely preys on birds.
These spiders can have a legspan up to 30 cm (12 in), a body length of up to 13 cm (5.1 in) and can weigh up to 175 g (6.2 oz). 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.
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.