Researchers realized hippos become airborne when they trot. They made the discovery watching footage that showed hippos fully lifting off the ground.
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Back in 1878, photographer Eadweard Muybridge helped solve a debate about how horses gallop.
Using cutting-edge technology for the time, he captured a series of images that showed they simultaneously lift all four feet off the ground.
It was something many had suspected of the graceful animal, and Muybridge's footage offered definitive proof. Nearly 150 years later, modern video footage has shown that hippos run in a similar way, and it's something no one expected.
Like horses, hippos also get a bit of air when they trot. There's a split second when the quickest animals fully leave the ground.
Researchers from the Royal Veterinary College made the discovery when viewing video footage of hippos romping around a theme park in North Yorkshire, England.
"We were pleasantly surprised to see how hippos get airborne when they move quickly," John Hutchinson, an RVC professor of evolutionary biomechanics, said in a statement. "It's really impressive!"
Johan Vermeulen/Royal Veterinary College
When elephants walk, they move their back left leg, front left leg, back right leg, then front right leg, according to The BBC. Scientists thought hippos moved in a similar way because of their enormous size.
However, when Hutchinson and RVC undergraduate student Emily Pringle watched footage of two hippos at Flamingo Land, the theme park, they saw something different. While it only lasted an instant — about 0.3 seconds — all four of the animals' feet did leave the ground at once.
To verify what they'd seen from the theme park, the researchers looked at more videos of hippos on the internet. Based on the movements of 32 hippos, they concluded that their trot is similar to horses.
Horses raise all their hooves during their faster strides, though not when walking. It's an uncommon gait for larger animals such as hippos, which can weigh over 4,000 pounds.
Knowing how the animals move could help veterinarians better diagnose hippos with mobility issues, the researchers said.
Hutchinson noted that while the hippos' gliding trot is impressive, it's not all that surprising that this is the first time it was documented.
The animals spend most of their time in the water and can be aggressive. "That's part of the reason why science knew little about how hippos move before our research," Hutchinson said.
The researchers published their findings in the peer-reviewed PeerJ journal. It remains to be seen whether the footage of the airborne hippos becomes as iconic as Muybridge's horse photos.
