The Goliath birdeater is a large spider that belongs to the tarantula family Theraphosidae. Found in northern South America, it is the largest spider in the world by mass and body length, and second to the giant huntsman spider by leg span. It is also considerably longer than the largest known prehistoric spider, Mongolarachne, that had a body length of 2.46 centimeters (0.97 in). 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.