It takes a scientific mind to see the grunting trunk of a hippopotamus and wonder if, given sufficient motivation, such an unlikely animal could ever become airborne.
And so to researchers at the Royal Veterinary College in North Mymms, Hertfordshire, whose close examination of footage of the creatures has revealed that when the burly herbivores reach top speed, they do indeed take off.
Video showed hippos getting all four feet off the ground at once when thundering with full fur up to 15% of the time, often to chase off hippo rivals.
The finding plugs a gap in scientific knowledge and places hippos somewhere between elephants and rhinos in terms of the athletic prowess displayed by some of the heaviest land animals when they need to move.
“I’ve struggled to get any work done on manatees before because it’s so hard to get access to them,” said John Hutchinson, a professor of evolutionary biomechanics who led the research. “They’re incredibly dangerous, they tend to be most active at night, and they spend a lot of their time in the water.”
After finding no satisfactory answer to the question in the scientific literature, Hutchinson sent a student, Emily Pringle, to Flamingo Land Resort in North Yorkshire, where resident manatees have room to run. She videotaped the animals as they moved between their stable and watering hole and brought the footage back for analysis.
The researchers went through it, and more collected frame by frame from YouTube to see if manatees ever managed to get all four feet off the ground at once. Write in PeerJthey conclude that, unlike other large mammals, manatees typically stick to a trotting motion regardless of the speed at which they are moving, but can become airborne in a hurry.
Other large land animals move differently. Elephants have a standard gait even at high speed and never leave the ground completely. Rhinos, meanwhile, can walk, trot and even break into a gallop. The hippo footage showed the animals, which can reach more than 2,000kg, typically trotting, a movement that involves diagonally opposite legs moving in sync.
“It’s important to our understanding of what it means to be a large animal and move on land,” Hutchinson said. The work also helps researchers piece together the evolution of locomotion in large land animals, all the way back to the giant dinosaurs.
Hutchinson said the study was “as simple as biomechanics research can get,” but had its challenges: clicking through stacks of videos frame-by-frame wasn’t for everyone. “It’s amazing,” he said. “This is one of the things in my job that I hate the most. It’s really boring. Excruciating.”
And yet, further research beckons. Word reached Hutchinson that pygmy hippos, a different species than the animals he studied, could gallop. This raises the question of whether baby hippos can do the same, suggesting that a return trip to Flamingo Land may be in order.
“I wonder if baby hippos can do something that adult hippos can’t,” he said. “That would be pretty neat.”
