Hippos are the third-largest land mammals. Their bulky bodies rest on stout legs with four toes each, and they have long, sharp canines used for fighting. Their incredibly powerful jaws can open to 180 degrees and can cut a human body in half. They’re also surprisingly agile and can climb steep banks each night to graze on grass.

The smooth, hairless skin of a hippo is greenish-black to blue-black on top and brown on the bottom. It’s sensitive to the fierce African sun and can burn or dry out quickly. They spend most of the day in water or mud to stay cool and hydrated. They’re also known to spray a pink fluid from their skin in an effort to protect themselves from the sun’s powerful UV rays. This oily secretion is commonly referred to as “blood sweat” even though it’s neither blood nor sweat, and it actually contains two acids whose light absorption range peaks around the UV spectrum.

Female hippos give birth to a single calf (baby hippo) at a time after a gestation period of eight months. They nurse their young calves for about 12 months.

Hippos are social creatures and hang out in groups of 10 to 30 individuals, or herds, led by a dominant male. They’re also famous for their aggressive behavior, with rival males standing nose to nose and bellowing loudly in a battle of the sexes. The best way to avoid a confrontation is to keep a safe distance!