Why Are Capybaras So Big?

Why do capybaras have such big teeth? Adrian had to know! To get to the bottom of this, we spoke to a biologist named Santiago Herrera Alvarez. Capybaras are Internet sensations, and Santiago can't get enough of them! Santiago's questions were even bigger than capybara teeth: how did capybaras, a relative of rodents like mice and rats, get to be so enormous? Tune in for a capybara rodeo, and stick around to find out how one little animal can grow to superstardom.

Learn more about biologist Santiago Herrera-Álvarez and the time he got to visit with baby capybaras in our bonus interview extra on Patreon!

A tan Capybara, a large hamster like rodent that is very cute, on a purple background with the title "Why Are Capybaras So Big" in fun white text.

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Biologist Santiago Herrera-Álvarez, who earned a master’s degree from Universidad de los Andes, Bogotá, Colombia, where he worked on the evolution of gigantism in the capybara.

Santiago Herrera-Álvarez, is a biologist at the University of Chicago. He researches the genetics of adaptation to toxin resistance in toad-feeding species and the evolution of gigantism in the capybara. In his spare time, Santi enjoys playing the guitar, walking by the Lake Michigan, and is a landscape photography aficionado.

Why Don't Big Animals Get More Cancer?

If you want to learn more about the genetics of large animals, and how it relates to cancer, check out this video from PBS! Why do whales, elephants, and other large animals not get cancer? Logically, the larger an animal is, and the longer it lives, the more likely it should be to get cancer. But these giants don’t. Why is that? And can the answer help humanity?

Why do whales, elephants, and other large animals not get cancer?

And, as promised, here are some videos of Capybaras being adorable and super chill.

CAPYBARA’s are unbelievably friendly and are happy to be chairs to other animals 😊

The largest rodent in the world is a Capybara—and they are VERY cute. Native to South America, these semi-aquatic gentle giants are known for their peaceful, sociable personalities. But there’s something special about the Capybaras in Japan’s Izu Shaboten Zoo - here they live a pampered life, drawing crowds of people to see them.

Along the banks of the Amazon River, the Capybara family watch over their young—keeping a close eye out for predators.

Is it a hog? Is it a beaver? Or is it a rodent of unusual size? Nope, nope and yes. Well, sort of. It's a capybara, the biggest rodent on Earth. Closely related to guinea pigs, these semi-aquatic creatures can weigh as much as a human at up to 90 kg (200 lbs). That's a big guinea pig. And though they're large and in charge, they're harmless. They've even been dubbed "nature's chairs," as they are so mellow, they let other animals sit on them. So why are these lovable giants so relaxed? Do they have any natural predators? And would they make good pets?