Watch a Mysterious Worm With an Anus for a Mouth

Hey there, hipster! Some worm is trying to steal your mustache.

Danish Ho caught this creepy crawly recently on camera and posted it to his Facebook page. He told National Geographic that he was hiking in the mountains in Malaysia on a beautiful day, spotting “monkeys, leeches, scorpions, snakes,” and then this peculiar animal, which he didn’t recognize. ("Watch: Bizarre Deep-Sea 'Worm' As Long As an Arm Revealed.")

Ho thought it might be some kind of snake and recorded it. Reader Terri Shofner then alerted us to Ho's video of the odd-looking creature, which experts say is likely an unknown species of the genus Bipalium, known by the common names hammerhead worm and broadhead planarian.

The video is unusual: Typically, these worms live underground, coming to the surface only when it's wet and dark, says Peter Ducey, a biologist at the State University of New York in Cortland.

But any opportunity to see the hammerhead up close is a window into a bizarre world.

Potty Mouth

For openers, the hammerhead worm's mouth and anus, located under their bodies, have similar functions. (Read about a giant sea cucumber that eats with its anus.)

When the worms are ready for lunch, their multitasking orifice unfolds “a sheet-like pharynx lined with glands" that "lays on top of the animal that it’s about to eat," usually earthworms, Ducey says.

The sheet secrets enzymes that liquify the prey, which they then suck up into a sort of meaty shake. Those wide heads are likely packed with sensory organs for picking up chemical trails of potential mates or prey.

Their gut branches throughout their bodies to spread nutrients, since the worms lack a circulatory system.

About a day later, the worms "release waste back out the same opening," he says.

Sex Positions

All Bipalium species are hermaphrodites, and so they're also flexible in how they make babies.

Some species exchange sperm via internal fertilization and then lay egg capsules in or on the ground, Ducey says.

Many can asexually reproduce by fragmenting.

"They leave off a piece of the body as they are crawling along the ground and then that piece would grow back all the necessary parts"—and voila, another worm, he says. (Related: "Pictures: 5 Animals that Regrow Body Parts.")

Some worms even employ both methods of reproduction.

Hammerhead Horror?

There are about a hundred species of broadhead worms, which vary in size from a few inches to a foot and can have beautiful colors and patterns, Ducey says.

Though there's extensive scientific literature on the genus, many of the individual worm species have not yet been classified, he adds. Scientists would need to collect DNA samples of the worm in the new video to identify it.

Some hammerhead worms have also become invasive outside Asia.

“Bipalium kewense has spread throughout the world among potted plants,” Mary Wicksten, a biologist at Texas A&M University, says via email.

This species "eats snails, other worms, and other tiny creatures—but it really grosses out unsuspecting gardeners when they see it," she says.

Hammerhead worms contain the same toxin as blowfish and can be harmful if eaten. Since so many species are unidentified, experts say to avoid handling any you may come across.

Seeing is Believing

Ho wrote in his message to National Geographic that he was curious if the animal had eyes. Bipalium worms do have many eye-like organs around the outside edge of their long heads, but little is known about how they work, Ducey says.

"They may sense light versus dark, but probably can't form any kind of images."

Because their heads are too soft to dig, hammerhead worms take up residence in holes made by other animals, adds Ducey—yet another intriguing fact about these sci-fi animals.

“Spielberg needs to know about this, right?”

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