We Knew That Hippo Races Were Fast, but We Didn’t Realize That They Spend 15% of the Race in the Air

In 1878, photographer Eadweard Muybridge answered a question that had puzzled zoologists and equestrians for years: Do horses ever gallop with all four legs in the air? Almost 100 years later, someone asked the same question.

Not about horses, but about hippos.

They run as if they're flying. The answer is a resounding "yes." Hippos lift all four legs off the ground when they run. But this “flight” lasts only 0.3 seconds, according to a study by two researchers at University of London.

This observation may come as a surprise, but it makes sense to experts in the behavior of these mammals. First of all, they state, we have to consider the animal’s size. Adult specimens usually weigh over a ton, with females weighing around 3,000 pounds and males reaching 3,500 to 9,920 pounds.

In addition, experts have long known that these animals are fast—amazingly fast, with some estimates putting their top speed at 18.6 miles per hour. This is more than fast enough to catch up with any unwary animal that gets too close.

​​Slow motion. To study the hippo’s movement on land, the team studied specimens at the Flamingo Land Resort in Yorkshire, England, which they recorded with high-speed cameras to watch their movements in detail. They supplemented this footage with a compilation of videos of specimens in the wild and at other centers. In total, the researchers obtained 169 cycles from 32 individual specimens.

15% of the time. Analyzing these videos allowed the team to better understand how these animals walk and how they move in general. For example, they observed that hippos, unlike elephants, move at a trot even when not trying to reach high speeds.

The hippos’ walking gait is unique compared to other large land mammals. Elephants, for example, have only one quadrupedal walking gait, which they use even when moving at higher speeds. their vary their walking gait and can trot and gallop like horses, depending on speed, but without lifting all four legs off the ground simultaneously.

The team behind the study explains that hippos can leave the ground for up to 15% of their running time. However, they rarely move at their maximum speed. They only do so when being chased by another hippo. The researchers published details of the study in the journal PeerJ.

A running colossus. The combination of mass and speed in these mammals makes them uniquely dangerous. They kill an estimated 500 people a year in their native Africa.

However, recent work can help us conserve the species by assisting veterinarians in identifying problems with these animals and improving the quality of life for hippos in captivity by facilitating the design of enclosures that better suit their needs.

This article was written by Pablo Martínez-Juarez and originally published in Spanish on Xataka.

Image | Filip Olsok

Related | Scientists Are Injecting Radioactive Material Into Rhino Horns on Live Animals to Prevent Us From Eating Them