World’s Biggest Spider Explained

In a world where even the smallest spiders can provoke a fearful shriek, Theraphosa blondi takes 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 is hard-boiled in a rolled leaf and tastes 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.

Follow Carrie Arnold on Twitter and Google+.

giant spider screengrab

Carrie is a freelance science writer living in Virginia. When she's not writing about cool critters, she's spending time outside, drinking coffee, or knitting. You can visit her website at http://www.carriearnold.com
  • km

    yeesh..lol..eww..and all the other words we use when we run across a reg spider, never mind that one..I know folks have em as pets, and I was reading about the molting process which is fascinating..great article..

  • Bart

    Update Flash?! Really! It’s 2013. 🙁

  • Carol Carter

    Eeeewww!…That’s such a big, disgusting spider!…..Everything is supersized down there!…..I would not make a good dinner guest with the indigenous tribes…..

    • Carrie Arnold

      I can’t say I would have taken a bite, either–although I think it’s good to step outside our comfort zones once in a while!

  • wayne

    Good one, you didn’t even bother to say or clearly show how big it is

    • Carrie Arnold

      The second paragraph says that they can weigh around 6 ounces. I looked up the legspan for you, and it’s about a foot across.

  • Leo

    The last name of the spider expert is HORMIGA(ANT)?????? Are you kidding me?

  • caroline keter

    Now that’s something i didn’t know that i now do. Great article. Interesting read.

  • Ito fernando

    Tasty?? Eeeww..

  • dare

    Looks just like my baby, Gilly. I have one. Beautiful creature.

    • Carrie Arnold

      I’m glad you like these amazing creatures. 🙂

  • Laura

    Someone please tell National Geographic that a T blondi is NOT a spider but a tarantula. There is a difference between the 2 so why, why can’t you get it right!!!

    • Carrie Arnold

      Good point. I did try to mention early on that T. blondi was a tarantula, however!

  • Raquel

    A tarantula is a type of spider, therefore ALL tarantulas are spiders.

  • Stephanie Wallace

    Beautiful tarantula. I have a few as pets but yet to add the bird eater,what a magnificent creature. :).

  • Stephanie Wallace

    Thank you for the information, these are amazingly beautiful tarantulas, I hope to see one in its native habitat one day.

    • Carrie Arnold

      Good luck on your search! Maybe one day I’ll be brave enough to go seek one out. 🙂

  • aida cadena

    I’m terrified and fascinated….but more terrified.

    • Carrie Arnold

      I totally understand your sentiment!

  • Francisco José R. Prestes

    A Theraphosa blondi é uma aranha da ordem araneae, subordem Opistothelae, infraordem mygalomorphae, família theraphosidae e subfamília theraphosinae. E a aranha do vídeo não é a espécie “blondi” e sim a “stirmi”, ou seja, Theraphosa stirmi que também alcança um tamanho gigantesco. Muito encontrada na região amazônica brasileira.

  • Doc_Anchovy

    Love all the multiple punctuation marks in this “scientific” comments area.

  • Benjamin T.A

    Wow the tarantula is really a big and scary kind of spider, but is there any big spiders in Africa?

  • dlut414

    considering getting one as pet

  • Eric Simpson

    Carrie Arnold, why did you agree to Laura of Florida’s comment about tarantulas not being spiders? Tarantulas are within the Order Araneae, and are therefore spiders.

    • Carrie Arnold

      I think we read the comment differently. I was agreeing that T. blondi was a tarantula–which it is. It’s also a spider.

  • danish turk khan

    i am to workiong on white widow having dfferent and 8 different species from last 7 year

  • stuart longhorn

    So, as others have said, why please is the spider used in the video and static image Theraphosa stirmi (from Guyana) and not the focal species of the article Theraphosa blondi (French Guyana/Suriname)? If you are going to talk about a certain species, it is potentially misleading to then show another, which can have a variety of different attributes. I expect the wrong images to be used in poor news reports but not National Geographic.

    • Carrie Arnold

      Stuart, I’m honestly not sure. I wasn’t in charge of the video for this post- I will ask and get back to you. Thank you for pointing this out. –Carrie

    • Christine Dell’Amore

      Thanks for the comment Stuart — I’m the editor of this blog. We added a line under the video to clarify that the species of tarantula in the video are not T. blondi. I agree with you that ideally it would have been better to have a video solely focused on T. blondi.

  • Carlos

    This is NOT the worlds biggest spider! Do your research before claiming such!

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