The world of spiders often sparks curiosity about the largest among them. Defining the “biggest” spider is not straightforward, as size can be interpreted in different ways.
Understanding “Biggest”
Defining the “biggest” spider requires considering different metrics. Scientists typically use two criteria: leg span and mass. Leg span measures the distance from the tip of the longest front leg to the tip of the opposite hind leg. Mass measures the spider’s body weight. Different spiders can claim the title of “biggest” depending on which measurement is prioritized.
The Goliath Birdeater
The Goliath Birdeater (Theraphosa blondi) is the world’s largest spider by mass and body length. Found in the rainforests of northern South America, this tarantula can weigh up to 175 grams (6.2 ounces) and have a body length of up to 13 centimeters (5.1 inches). Its robust body is covered in fine, russet-brown to black hairs, and it possesses distinct spines on its third and fourth pairs of legs.
Despite its name, birds are not its primary food source; the name originated from an 18th-century engraving. Its diet primarily consists of insects, worms, amphibians, and small rodents, which it ambushes on the forest floor.
When threatened, this nocturnal spider employs several defense mechanisms. It can rub its legs together to produce a hissing sound, a process called stridulation. The Goliath Birdeater can also flick urticating hairs from its abdomen, which cause irritation to predators’ skin and mucous membranes.
Its fangs are long, and it can bite, though its venom is considered mild and comparable to a wasp sting for humans. Bites are typically a last resort, as the spider prefers to display defensive behaviors first.
The Giant Huntsman Spider
The Giant Huntsman Spider (Heteropoda maxima) holds the record for the largest leg span. Its leg span can reach an impressive 30 centimeters (11.8 inches), roughly the size of a dinner plate. While its body length is comparatively smaller, its elongated legs give it an expansive reach.
This spider’s flattened body allows it to navigate tight spaces, beneficial in its cave habitat. Unlike many spiders that build webs, the Giant Huntsman Spider is an active predator. It relies on speed and agility to pursue and ambush insects and small reptiles.
Its venom immobilizes prey but is not considered medically significant to humans, typically causing only mild symptoms. Despite its imposing size, this reclusive spider is more inclined to flee from human interaction than to attack.