What is the largest spider by mass, a nocturnal tarantula?

The Goliath birdeater is the largest spider by mass and one of the largest spiders known overall. This nocturnal tarantula, Theraphosa blondi, lives in the rainforests of northern South America, especially in parts of Brazil, Guyana, Suriname, French Guiana, Venezuela, and Colombia.

Its name is misleading: it rarely eats birds. The “birdeater” label traces back to an early 18th-century illustration by Maria Sibylla Merian that depicted a related tarantula eating a hummingbird. In reality, the Goliath birdeater mainly hunts large insects, worms, amphibians, and other small vertebrates.

Adults live in or near deep ground burrows and emerge at night to hunt. They subdue prey with venom, then liquefy its internal tissues and drink the resulting fluid. The species can reach a body length of about 13 cm, a leg span near 30 cm, and a mass approaching 175 g.

It is not the record-holder for leg span: that distinction belongs to the giant huntsman spider. The Goliath birdeater holds the more specific record for greatest spider mass.