Spiders often spark human curiosity, especially regarding their impressive sizes. Identifying the largest among them is a common question, though the answer can be nuanced due to different measurement methods.
The Goliath Birdeater: King of Size
The Goliath Birdeater (Theraphosa blondi) is most frequently recognized as the largest spider by both mass and body length. This tarantula can achieve a leg span of up to 12 inches (30 centimeters), comparable to a dinner plate. Its body can reach 5.1 inches (13 centimeters) and weigh up to 6 ounces (170-175 grams), making it the heaviest known spider.
It has a hairy body, ranging from tan to black. The Goliath Birdeater inhabits the humid rainforests of northern South America, including Suriname, Guyana, French Guiana, northern Brazil, eastern Colombia, and southern Venezuela. It is a nocturnal species, preferring deep burrows in marshy or swampy areas. Despite its name, this spider rarely preys on birds, primarily feeding on insects, frogs, worms, and small mammals.
Defining “Biggest”: Leg Span vs. Body Mass
Size can be quantified in different ways. The two primary metrics are leg span, which measures the distance from the tip of the front leg to the tip of the hind leg on the opposite side, and body mass or weight, which indicates the spider’s overall bulk. While the Goliath Birdeater holds the record for body mass and overall body length, another species often competes for the title of largest based on leg span.
The Giant Huntsman Spider (Heteropoda maxima) possesses the largest known leg span, potentially reaching up to 12 inches (30 centimeters). Although its leg span can match or even slightly exceed that of the Goliath Birdeater, the Giant Huntsman has a much lighter build. Its body is significantly smaller, around 1.8 inches (4.6 centimeters) in length, and it weighs considerably less, around 5.9 ounces (167 grams). This spider is characterized by its long, crab-like legs that splay outwards, allowing it to move sideways with agility. The Giant Huntsman Spider is primarily found in Laos, often inhabiting caves.
Other Notable Giants
Beyond the Goliath Birdeater and the Giant Huntsman, several other spider species are notable for their considerable size. The Brazilian Salmon Pink Birdeater (Lasiodora parahybana) can reach a leg span of up to 10-11 inches (25.4-28 centimeters), with females sometimes weighing over 3.5 ounces (100 grams). It is native to eastern Brazil and known for its bulky appearance and distinct salmon-pink hairs.
The Hercules Baboon Spider (Hysterocrates hercules) is another large arachnid. This rare African tarantula, found in Nigeria and Cameroon, has an estimated leg span of around 8 inches (20.3 centimeters). Its reclusive nature means much about its habits and true size remains mysterious, with only a few documented specimens, including one at the Natural History Museum in London.