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World's Biggest Spider Explained

This giant tarantula spans nearly a foot and weighs as much as a baseball, but might not be as terrifying as its reputation suggests.

World's Weirdest: World's Biggest Spider

With a leg span nearly a foot wide, the goliath bird-eater is the world's biggest spider. And it has a special defense mechanism to keep predators from considering it as a meal.

In a world where even the smallest spiders can provoke a fearful shriek, Theraphosa blonditakes scare tactics to a whole new level.

This South American tarantula holds the record for world’s largest spider. Other spiders might have longer legs, but T. blondi‘s large body means its overall weight can reach 6 ounces (170 grams).

Commonly known as the Goliath birdeater due to an 18th-century engraving showing another member of the tarantula family eating a hummingbird—which gave the entire Theraphosa genus the nickname of “bird eaters”—the gargantuan spider is not quite as menacing as it might seem.

Despite its nickname, T. blondi only rarely devours birds, notes the Encyclopedia of Life. According to spider expert Gustavo Hormiga at George Washington University, T. blondi mostly eats arthropods.

“They are general predators, and if they run into other vertebrates like a small mouse or lizard, they can eat those, too,” Hormiga says.

But don’t expect this Goliath to use a giant web to snare its prey—T. blondi hunts for its meals the old-fashioned way, using its large fangs to bite and kill. (Watch video: “How to Survive a Giant Tarantula Encounter.“)

Like most spiders, T. blondi produces venom, although Hormiga notes that it’s not particularly toxic to humans. The bites have been described as feeling like wasp stings, but they almost never require medical attention.

Beware the Hair

Although T. blondi doesn’t weave a web, it does produce and use silk. The spider lives in burrows beneath the forest floor, which it lines with silk to give the structure more stability. Should a mammal try and dig up the burrow for a tasty spider snack, T. blondi has a weapon more useful than venom: urticating hairs on its abdomen. (The technical term is bristles, as only mammals have hair, but even scientists use the more popular term in conversation.)

“These are shaped like little harpoons if you look at them under the microscope,” Hormiga says, which gives the hairs the ability to embed in the skin.

“These spiders very quickly rub their fourth pair of legs on their abdomen to release the hairs, which then become airborne. These are very itchy.” (Related: “Tarantulas Shoot Silk From Feet, Spider-Man Style.”)

The urticating hairs don’t need to be airborne to do their damage, however—researchers and owners of pet spiders need to handle the Goliath birdeaters with gloves. To large animals like humans, the hairs are merely irritating and itchy, but they can be fatal to smaller mammals like mice.

T. blondi females lay between 50 and 150 eggs in a giant sac that can measure over an inch (30 millimeters) in diameter. They cover the sac in urticating hairs to keep predators away.

It takes about two to three years for these hatchlings to mature; they spend significant amounts of time living with their mother in her burrow until they get old enough to fend for themselves. Although females can live up to 20 years, males have a life-span of only 3 to 6 years, often dying soon after reaching maturity and mating.

Tastes Like Prawns?

Many of the locals in northeastern South America regard T. blondi as a tasty snack. They first singe off the urticating hairs, then wrap the spider in banana leaves to roast. Tarantula expert Rick West, who once sat down for a meal of these spiders with the local Piaroa peoples of Amazonas in Venezuela, says T. blondi can be surprisingly tasty and moist. (Also see “U.N. Urges Eating Insects; 8 Popular Bugs to Try.”)

“The white muscle ‘meat’ tastes like smoky prawns, while the gooey abdominal contents are hard-boiled in a rolled leaf and taste gritty and bitter,” West says. “The three-quarter-inch (two-centimeter) fangs are used after the meal as toothpicks to remove T. blondi exocuticle from between one’s teeth.”

It’s not often that your dinner comes with built-in toothpicks. Despite its shrimp-like taste, however, you probably won’t see Goliath birdeater on a restaurant menu any time soon.

Related: Watch This Tarantula Crawl Out of Its Own Skeleton

For over three hours, this female Mexican Red Knee tarantula molts its exoskeleton. It'll take several days for the new exoskeleton to fully harden.