The Biggest Spider in the World: Heaviest vs Widest Legs

On a rainforest floor in northern South America, a hairy brown spider the size of a dinner plate waits at the mouth of its silk-lined burrow. Thousands of kilometres away, in a cave in Laos, a flatter, longer-legged spider spreads out across the rock.

Which is the biggest spider in the world? It depends how you measure. The heaviest is the Goliath birdeater (Theraphosa blondi), at up to about 170 to 175 g (6 oz), says Guinness World Records. The widest leg span may belong to the giant huntsman (Heteropoda maxima) of Laos, at 25 to 30 cm (10 to 12 in).

What is the biggest spider in the world?

The Goliath birdeater is the biggest spider by mass. Guinness World Records calls it the world’s largest known spider by weight, at up to 175 g (6.2 oz). A spider called Rosi, bred in captivity in the UK, weighed 170 g (6 oz) in 1998 with a leg span of 28 cm (11 in). If “biggest” means widest legs, the giant huntsman may win instead.

The two biggest spiders, measured two ways

Spider	Leg span	Weight	Body length	Source
Goliath birdeater (Theraphosa blondi), northern South America	About 28 cm (11 in); National Geographic says up to 30 cm (12 in)	Up to about 170 to 175 g (6 oz)	Not given by our sources	Guinness World Records; National Geographic; Virginia Zoo
Giant huntsman (Heteropoda maxima), Laos	25 to 30 cm (10 to 12 in)	Not published	Over 46 mm (1.8 in)	Jäger 2001, Zoosystema

Leg span is measured across the outstretched legs, and it depends on how the legs are posed. That is why two spiders of very different weights can both be called “the biggest”.

How big is the Goliath birdeater?

A big Goliath birdeater has a leg span of about 28 cm (11 in) and weighs around 170 g (6 oz). The Virginia Zoo gives a leg span of 11 inches and a weight of 6 ounces. National Geographic gives up to 12 inches (30 cm) and 6 ounces.

Guinness lists two record spiders. One was reportedly collected in Venezuela in 1965 with a leg span of 28 cm. The other, Rosi, was a captive spider weighed at 170 g. So the heaviest weight on record comes from a pet spider, not a wild one, and wild spiders may weigh less.

What is the giant huntsman spider?

The giant huntsman is a long-legged spider from Laos, described by the spider scientist Peter Jäger in 2001. In his paper in Zoosystema, he wrote that it could be the largest huntsman spider, with a body over 46 mm long and a leg span of 250 to 300 mm.

Notice the “could”. Jäger even ended his title with a question mark. The specimens are kept at the national natural history museum in Paris, and he suggested the species may live in caves. No weight has been published, and its slim body is far lighter-looking than a Goliath’s. To learn more about this family, see where huntsman spiders live.

Where does the Goliath birdeater live?

The Goliath birdeater lives in the rainforests of northern South America. The Virginia Zoo lists Suriname, Guyana, northern Brazil and southern Venezuela, in upland rainforests, marshes and swamps. It lives in a burrow under the forest floor, which it lines with silk, says National Geographic.

Does the Goliath birdeater really eat birds?

Rarely. Despite the name, it eats mostly insects and earthworms. National Geographic says insects make up most of its diet, with frogs and rodents sometimes on the menu and birds only rarely. The Virginia Zoo says it eats mostly earthworms, and occasionally small rodents, amphibians and reptiles.

Is the biggest spider in the world dangerous?

Not to people. Its venom kills small prey, but a bite to a human would sting about as much as a wasp’s, says National Geographic. The bigger nuisance is its hairs. It can flick off barbed hairs, called urticating hairs, that make skin and eyes itch and sting.

Even researchers wear gloves to handle one, National Geographic reports, so these spiders are best watched rather than held. The Virginia Zoo names the exotic pet trade, along with habitat loss and hunting, as major threats, so the kindest way to see one is at a zoo.

How long does the biggest spider live?

Females live far longer than males. National Geographic gives about 20 years for females and 3 to 6 years for males. The Virginia Zoo gives 12 to 16 years in the wild and into the early 20s in human care. Females lay egg sacs holding 50 to 150 eggs, National Geographic says.

What role does the Goliath birdeater play in the rainforest?

It is a ground-level hunter. By eating insects, earthworms and the odd frog or rodent, it is one of many predators that keep these animals in check on the forest floor. In turn, it is hunted itself, which is why it carries a coat of stinging hairs. Its future is tied to the forest: habitat loss is one of the main threats the Virginia Zoo names.

Myths about the biggest spider

Myth: The Goliath birdeater mainly eats birds.

Fact: It eats mostly insects and earthworms, and birds only rarely. Why people believe it: the name. National Geographic traces it to an 18th-century engraving of a related tarantula eating a hummingbird.

Myth: The biggest spider’s bite can kill a person.

Fact: Its venom is about as strong as a wasp sting, say National Geographic and the Virginia Zoo.

Myth: There is one clear “biggest spider”.

Fact: The Goliath birdeater is heaviest, but the giant huntsman may have a wider leg span. The answer depends on what you measure.

Test yourself

1. Which spider is the heaviest?

The Goliath birdeater, up to about 170 to 175 g.

2. Which spider may have the widest leg span?

The giant huntsman of Laos, 25 to 30 cm.

3. What does the Goliath birdeater mostly eat?

Insects and earthworms, not birds.

Frequently asked questions

Sources

1. Guinness World Records. Largest spider.
2. Jäger, P. (2001). A new species of Heteropoda (Araneae, Sparassidae, Heteropodinae) from Laos, the largest huntsman spider? Zoosystema 23(3): 461-465.
3. National Geographic. Goliath birdeater.
4. Virginia Zoo. Goliath birdeater.
5. National Geographic. World’s biggest spider explained.

Sources checked 12 October 2026.