While exploring the jungles of Mulu in Borneo, wildlife photographer Brad Josephs encountered a black-and-white worm with a split head. (We're saying it: Beetlejuice, Beetlejuice, Beetlejuice!) The creature is strange, no doubt, but it's no mutant. This is a land planarian, a perfectly healthy – and surprisingly common – predatory flatworm in the genus Bipalium


Bipalium roughly translates to "two spades", a nod by early naturalists acknowledging the worm's resemblance to a pickaxe. Also known as "hammerhead" or "arrowhead" worms, planarians can be found from Japan to the Americas – if you know where to look. 

Despite being known to science for some 300 years, there are still a lot of gaps in this group's ecological story. Planarians have been observed in the US only since the early 1900s, so it's thought that they hitchhiked their way west on traded horticultural plants, but that's just our best guess.

Most planarian worms spend their time scooting through the soil like the Japanese wonder you see above, but these animals inhabit a wide range of habitats. Some have even adapted to life in the savannah, swapping the typical diet of earthworms and slugs for one composed mostly of termites and their larvae. 

As for that shark-style "two face", it all comes down to matters of the sensory sort. Hammerhead worms have no true eyes, but the head is packed with a tightly bundled mass of nerve tissue, which connects to nerves throughout the worm's body. 

Something else is also lacking here: a complete digestive system. The worms possess no anus; instead, they vent undesirable matter back through their mouths. When prey is located, the universal orifice extends, exposing a system of circular muscles that help the planarian slurp up its target. Once inside, prey items are broken down, digested and regurgitated as a slimy trail of majestic egesta. No food in sight? No problem! Planarians can go for weeks without eating – and they can also opt to feed on their own reproductive tissue when the going gets tough!

So there you have it, folks. A hammerhead mouth-pooper that can eat its own sexy bits. Nature is beautiful. 


Top header image: Andreas Kay/Flickr