5 Weird and Wonderful Hippo Facts

The humble hippopotamus is currently at risk of habitat loss. Currently listed as ‘vulnerable’ on the IUCN, it is vital to raise awareness about this keystone species, as they are simply amazing; without them, the balance of the ecosystem would be forever disrupted. 

To help raise awareness and keep hippos in your mind, here are five fascinating hippopotamus facts that may be slightly weird but definitely wonderful. 

Hippos are closely related to whales and dolphins 

They are distant cousins. Whippomorpha is a group of animals that includes hippos and cetaceans (whales, dolphins and porpoises). DNA only found in these creatures indicates that they had a common ancestor 60 million years ago - the Anthracotheres.

Hippo sweat is red

Believe it or not, this is not a myth! Hippos secrete an oily red ‘sweat’ that turns from colourless to red within a few minutes. Acting as a sunscreen, hippo sweat keeps their skin moist and protects against the sun by scattering the light. Scientists are studying these properties to improve commercial sunscreen, but also for infection prevention.

Hippos can’t swim

They are too heavy! We know that hippos are the heaviest and second-largest land mammal in the world; males can weigh 4,500 kg. Due to their sheer size and density, hippopotamuses can’t float. They walk (or bounce) across the bottom of rivers and lakes. 

Hippos sleep underwater 

A weird fact about hippo behaviour is that they have a unique reflex that allows them to sleep underwater and bob up for air without waking up. Hippos sleep for around 10 hours at night and nap throughout the day. 

Hippos can close their ears and nose

Like cetaceans, hippos have valvular nostrils that they can close to stop water from getting in. This adaptation is crucial for their ability to hold their breath underwater for up to five minutes, and is why hippo calves can suckle underwater.