Do Any Worms Have Teeth?

It's a good thing Pristionchus pacificus only grows to a length of 1 millimeter, just large enough to be seen with the naked eye, because you wouldn't want him coming after you. The nutrition in this worm's early life determines his adult feeding habits. If the baby nematode, or roundworm, gets enough bacteria to eat in his larval stage, he'll grow up to have a small mouth with small teeth. If his childhood diet is skimpy, he'll be able to make up for lost time as a mature worm by developing a big mouth containing "one or two teeth akin to the fangs of a snake," writes Stanford University neuroscientist Samata Katta. P. pacificus then goes hunting other nematodes, sinking his fangs into them and sucking out their insides.

What happened to an Australian couple after a camping holiday in the outback was so shocking that it made news headlines around the world. Less than two weeks after cooking and eating a fish they'd caught, they both felt so sick that they sought medical treatment. Symptoms included large, itchy swellings and the sensation that something was moving under their skin. Doctors determined that eggs in the flesh of the fish they'd eaten had hatched into larvae with teeth so sharp that nothing prevented them from chomping their way anywhere they wanted to go in the couple's bodies. The culprit was the gnathostomiasis nematode, never before seen in Australia, but common in some regions in Asia and increasingly in Mexico and Latin America. Following months of painful and largely experimental treatments, doctors finally declared the couple worm-free.

Not everybody believes the leading story of how the bobbit worm got its name, although it was somewhat legitimized in an article published in 2011 in the journal "Revista de Biología Tropical." "Bobbitt" was the surname of a man whose enraged wife famously chopped off half his penis during a 1993 domestic dispute. Though the bobbit worm has never been known to specifically target the human groin area, his jaws are strong enough to cut a fish in half, and if he bites you, it's really going to hurt. He lives in warm ocean waters all over the world, ranging in length from 3.5 to 10 feet. Lurking unseen in his burrow in the sand, he waits for prey to happen by. When it does, he shoots out with lightning speed, grabs it in his teeth, then retreats back into his burrow to feast.

The king ragworm, also known as the sandworm, grows to lengths of almost 4 feet, inhabiting shallow, brackish water in temperate zones of the northern hemisphere. Like the bobbit worm, he also darts up from a burrow to seize his hapless prey in two needle-sharp teeth.

There's no dispute that the Mongolian death worm of the Gobi Desert has a horrifying number of teeth -- that is, if he actually exists. Called Olgoi Khorkhoi in the Mongolian language, this creature allegedly resembles an enormous, thick, blood-red intestine as tall as a man. Eyewitness accounts abound, but numerous expeditions that have gone in search of physical proof have all returned without it. When riled, the death worm is said to rear up out of the sand and spit a yellow corrosive liquid at the people or animals who have disturbed his rest. Even though the two heat-resistant subspecies of earthworm found in 2013 in the Gobi Desert bore no resemblance to the death worm, their discovery reawakened speculation that the creature might be more than merely a figment of Mongolians' imaginations.