Hippos are among the largest animals on Earth. Males weigh over three tons and are among the most dangerous animals anywhere. They owe their name to their affinity for water; in Greek, “hippopotamus” literally means “river horse.” These characteristics make them challenging subjects for scientific study. However, researchers from the Royal Veterinary College (United Kingdom) have taken on this challenge.
Trotting Hippos
In the journal PeerJ, the researchers describe how they analyzed the gait of approximately thirty hippos using videos taken at Flamingo Land Resort (United Kingdom). They found that hippos almost exclusively trot. This means that when they move, they simultaneously advance one front leg and the opposite hind leg, regardless of whether they are moving slowly or quickly. For comparison, elephants can walk by moving their two left legs at the same time, and horses, like rhinoceroses, start to gallop as they pick up speed.
Interestingly, when hippos increase their speed, they do not gallop. Instead, the researchers suggest that they can remain airborne for significant periods—up to 15% of their stride cycle, which equates to about 0.3 seconds. During this brief period, they appear to be flying.
Such Massive Animals Don’t Normally Fly
While horses can also appear to fly when running very fast, the researchers emphasize that this phenomenon is quite unusual in animals as large as hippos. For instance, we wouldn’t expect to see an elephant rising into the air—except perhaps the one our children know for its oversized ears.