The Goliath birdeater is the king of spiders. Weighing up to six ounces and with a leg span of nearly a foot, this tarantula is the largest arachnid on the planet.
Goliaths don’t usually eat birds, but they are big enough to be able to—and occasionally they do. “Birdeater” came from an 18th-century engraving that showed another kind of tarantula eating a hummingbird, which gave the entire Theraphosa genus the name birdeater.
Goliath birdeater diet
Insects make up most of the Goliath diet, but frogs and rodents are on the menu too. Goliaths prowl the Amazon in northern South America. When a Goliath pounces on a mouse, for example, its inch-long fangs act like hypodermic needles, pumping neurotoxins into the hapless prey. The spider then drags the dying animal back to its burrow and begins the digestion process. Spiders can’t ingest solid material, so they first liquefy the prey’s insides, then suck it dry.
Unusual defense
Unlike jumping spiders, Goliath birdeaters have bad eyesight. They rely instead on modified leg hairs, sensitive to vibration, to warn them of danger. If a predator like a coati gets too close, the Goliath has an unusual weapon: harpoon-shaped hairs (called urticating hairs) tipped with stinging barbs. The spider rubs its legs together, launching a shower of miniature missiles into the air. The hairs connect with the would-be assailant’s eyes and skin, sending it scurrying.