Hippo poop stinks — in more ways than one!

This is Sandra Tsing Loh with the Loh Down on Science.

In Tanzania, Africa, hippos are big. And they leave a big mark. How big?

These large mammals generate over fifty-two-thousand metric tons of dung each year! People originally thought that all this poop was beneficial. When hippos move between wading pools to feed and keep cool, they spread nutrients… well poop… throughout the ecosystem.

Meet Keenan Stears and colleagues at the University of California, Santa Barbara. They studied water quality and fish diversity in hippo pools along Tanzania’s Great Ruaha River. Turns out all this doo-doo does more harm than good!

Poop introduces microbes that remove oxygen from the water during the dry season. And fish need oxygen. As a result, the tilapia population dropped forty-one percent!

Tilapia are a MAJOR food source for locals. Stears urges local communities to be very careful when planning dams that would restrict water flow even further. That would cause a build-up of hippo poop, leading to more fish die-offs.

So when it comes to conservation, hippos are. . . Number Two?