Hippo Day

What the day is

Hippo Day is observed on February 15. It celebrates the hippopotamus, a semi-aquatic African mammal that is among the largest land animals alive and one of the most misread.

Origin and background

The origin of the observance is not documented.

The animal itself rewards the attention. Adults commonly weigh between 1,500 and 3,000 kilograms, and despite that bulk they can run faster than a person over short distances. They spend their days submerged to stay cool and out of the sun, then leave the water at night to graze, often walking several kilometers to do it.

Their nearest living relatives are not pigs, as the shape implies, but cetaceans: whales, dolphins and porpoises. The two lineages split many millions of years ago, and the evidence is genetic as well as anatomical.

The reddish fluid they secrete, often described as blood sweat, is neither blood nor sweat. It is a pigmented secretion that absorbs ultraviolet light and appears to inhibit bacterial growth, functioning as sunscreen and antiseptic for an animal with no fur and frequent skin injuries.

They are also genuinely dangerous. Hippos are highly territorial in water and readily aggressive toward boats and people, and they cause a substantial number of human deaths in Africa each year. Common hippos are listed as vulnerable, with populations reduced by habitat loss and hunting; the smaller pygmy hippo of West African forests is endangered and far rarer.

One population exists where it should not. Hippos imported to Colombia for a private zoo by the drug trafficker Pablo Escobar escaped after his death and have bred into an invasive population that authorities are still deciding how to manage.

How to take part

• Read about the whale relationship. It reframes the animal entirely.
• Support a conservation organization working on African river habitats, which is where the real pressure is.
• Visit a zoo with a hippo pool and watch how much time they spend fully submerged.
• Retire the cartoon image. Hippos are not gentle, and that misconception is why tourists get hurt.