How Big Is the Biggest Spider in the World?
Ask for the world’s biggest spider and you get a fight, not a winner. By sheer mass and body length it is the Goliath birdeater, heavy as a young puppy and the size of a dinner plate. By leg span it is the giant huntsman, all reach and almost no weight. Both are correct; they are just answering different questions.
See it to scale
Pick a spider and a familiar object. The leg span is drawn over it at the same scale.
The heaviest spider alive at up to 175 g — about a young puppy — on a body that reaches 13 cm. It rarely eats birds despite the name.
Spider drawing is representational; the leg-span width and the object are drawn to the same scale. Weights are typical maximums.
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Two different champions
The Natural History Museum in London hands out the records by category, and that is the honest way to do it. Heaviest body, longest legs and biggest web go to different spiders. For weight and body length, the Goliath birdeater (Theraphosa blondi) wins outright; for leg span, the giant huntsman (Heteropoda maxima) edges ahead.
Entomologist Piotr Naskrecki, who has handled wild Goliaths in the field, put the gap in plain terms to Live Science: comparing the hefty birdeater to the spindly huntsman is “like comparing a giraffe to an elephant.” Same height bracket, completely different animal.
The Goliath birdeater: heaviest by far
Native to the rainforests of northern South America, the Goliath reaches a body length around 13 cm, a leg span near 28 cm and a mass measured up to 175 g — heavier than a baseball, comparable to a young puppy. Its feet have hardened, clawed tips that Naskrecki said make an audible clicking, “not unlike a horse’s hooves.”
The name oversells the menu: it rarely eats birds, taking mostly insects, frogs and the odd rodent. Its real defence is a cloud of irritating urticating hairs it flicks from its abdomen. In parts of South America it is itself food — roasted in banana leaves, per National Geographic.
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The giant huntsman: longest legs
The giant huntsman is a newcomer to science — first identified in 2001 from a cave in Laos. The record individual reached a 30 cm (roughly 12-inch) leg span, the widest of any spider, on a body only about 4.6 cm long. It spins no web, instead ambushing prey on cave walls with those long, crab-like legs.
That slim build is exactly why it loses the overall “biggest” title to the Goliath: enormous reach, very little mass. If your question is “widest,” the huntsman wins; if it is “heaviest” or “most spider,” it does not.
The next tier down
Only one species comes meaningfully close on bulk: the Brazilian salmon pink, with a leg span around 26 cm. After that the contenders are regional record-holders — the Chaco golden knee of Paraguay and Argentina at roughly 20 cm, and Cerbalus aravaensis, a sand-dwelling huntsman from the Israel-Jordan border described in 2010, at about 14 cm. Out of more than 50,000 known spider species, genuine giants are a very short list.
Sources
- Natural History Museum, London — “The world’s most extreme spiders”: Goliath birdeater heaviest, giant huntsman longest legs (up to 30 cm).
- Live Science / Piotr Naskrecki — Goliath up to 175 g, dinner-plate span, clicking feet, “giraffe to an elephant” comparison.
- IFLScience & WorldAtlas — Goliath 28 cm span / 13 cm body; giant huntsman described 2001 in a Laotian cave, 30 cm record span.
- National Geographic — Goliath birdeater rarely eats birds; roasted as food in parts of South America.
Frequently asked questions
Related
One spider is the size of a dinner plate; another is the weight of a puppy. Ask which is biggest and the only honest reply is: in which direction?