This week, we’re talking about everyone’s favorite tarantula: Polly, the Goliath Birdeater! Polly is easily one of MBHI’s most popular animals, mostly because she’s hard to miss. Weighing in at whopping 6 ounces, and boasting a body length of 4.5 inches, the Goliath Birdeater is the largest spider in the world by mass and size.
The Goliath Birdeater (Theraphosa blondi) is not only characterized by its massive size. Tarantulas are often recognized because they’re “fuzzy.” The hairs on the body and legs of tarantulas are actually sensory structures known as setae. Since tarantulas are mostly blind, they use the setae on their legs and body to detect movement. Some species, including T. blondi, can rub the setae on their legs and pedipalps to produce a loud stridulation or hissing noise when provoked. I’ve worked with Polly quite a bit and know her behavior well, but her stridulation still makes me jump. It’s an effective tactic!
T. blondi and other tarantulas in the genera Theraphosa get their common name,”birdeater” or “bird-eating spider,” from an early copper engraving by the naturalist Maria Sibylla Merian. Merian observed a tarantula capture and eat an injured hummingbird while traveling in Suriname. Despite this behavior being the exception rather than the rule, the name “bird-eating spider” stuck. While Goliath Birdeaters are capable of eating small birds, they are terrestrial spiders, meaning they spend their life in burrows on the forest floor. Their typical lunch fare includes rodents, small reptiles, insects… and sometimes, other spiders.