Photos: Fossilized Tracks of Swimming Hippos

Ancient Hippo Tracks

(Image credit: Courtesy of Matthew Bennett)

Researchers in Kenya have uncovered fossilized animal tracks, which they believe may have been left by swimming hippos 1.4 million years ago.

Bottom-Walker

(Image credit: Courtesy of Matthew Bennett)

Recent excavations in the Koobi Fora region near Lake Turkana revealed dozens of animal tracks. A majority of the prints, like the one shown here, appear to have been left by a four-toed animal "bottom walking" in a shallow water body, the researchers say.

Toenails

(Image credit: Courtesy of Matthew Bennett)

Toenail marks were visible in some of the tracks. The central two toes are more prominent in hippos, and these digits may have scratched at the lake bottom during swimming.

Swimming Hippos

(Image credit: Courtesy of Matthew Bennett)

For a modern comparison, the researchers videotaped two female common Nile hippopotamues (Hippopotamus amphibius) through the side of a glass walled tank at the Adventure Aquarium in Philadelphia in 2008.

Hippo Feet

(Image credit: Courtesy of Matthew Bennett)

Hippos have distinctive feet with four digits.

Gliding Hippo

(Image credit: Courtesy of Matthew Bennett)

Underwater, the Nile hippos would glide with their limbs folded beneath their bodies, occasionally pushing off the bottom of the tank with one leg, only making contact with their digits.

Pushing Off

(Image credit: Courtesy of Matthew Bennett)

Sometimes, the hippos would thrust upwards towards the water surface using both hind feet placed firmly apart.

Megan Gannon
Live Science Contributor
Megan has been writing for Live Science and Space.com since 2012. Her interests range from archaeology to space exploration, and she has a bachelor's degree in English and art history from New York University. Megan spent two years as a reporter on the national desk at NewsCore. She has watched dinosaur auctions, witnessed rocket launches, licked ancient pottery sherds in Cyprus and flown in zero gravity. Follow her on Twitter and Google+.