No stick-in-the-muds! How galloping hippos 'fly' through the air at speeds of 18mph despite their not so graceful body types

By any reckoning, hippos are hardly the most graceful of creatures.

But they can be deceptively light on their feet and - at their fastest - are capable of moving with all four hooves in the air as they run, research reveals.

Scientists have been surprised by the findings given that hippos spend much of their time in water. Meanwhile, similarly heavyweight mammals such as elephants are quite unable to gallop.

Even running as fast as they can, elephants always have at least one leg on the ground at anyone time.

But hippos, who can hit top speeds of 18mph, are in effect ‘flying’ for 15 per cent of when they are trotting on land.

The new insight has come about from Professor John Hutchinson at the Royal Veterinary College and researcher Emily Pringle.

They collected footage of hippos from Flamingo Land in Yorkshire, and analysed footage of the animals running taken from the internet.

In total, the researchers combed through 169 cycles of locomotion from 32 individual hippos.

The analysis of the video footage revealed for the first time that the fastest-moving hippos become airborne, sometimes for substantial periods - about 15 per cent of the stride cycle or 0.3 seconds.

Professor Hutchinson said: ‘Our study was about as simple as biomechanics research can get. Anyone can take a camera or internet videos and learn something about how animals move from that footage.

‘It’s hard to work with hippos as they tend to stick to the water, and very seldom are trained to be studied in zoo collections.

‘They’re also very dangerous. That’s part of the reason why science knew little about how hippos move before our research.

‘We’re thrilled to provide the first study purely focused on revealing how hippos walk and run. We were pleasantly surprised to see how hippos get airborne when they move quickly - it’s really impressive!’