Dangerous Animals

Updated February 21, 2017 | Factmonster Staff

Fascinating but Deadly
Hippopotamuses, crocodiles, and hyenas

by David Johnson

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In cartoons, hippos are invariably brightly colored, cheerful, and fun. In reality, hippos are mean and aggressive, killing more people in Africa than any other animal. They are the third-largest land animal in the world, behind the elephant and the rhinoceros, weighing up to 9,000 pounds. Even pygmy hippos weigh 350 to 600 pounds. Hippos spend most of their days in rivers and lakes, where they feed on aquatic plants. At night they feed on land.

Highly territorial, hippos have been known to capsize a boat and bite off the head of the hapless sailor. This is easy since their tusks can reach 28 inches long and their mouths can open four feet wide. It is also extremely unwise to get between a hippo and her young, either in the water or on land, where they can run up to up 20 miles per hour.


The prehistoric crocodile is a ruthless and feared hunter. It is the largest and most intelligent reptile. There are 26 species, the largest of which, the saltwater crocodile, can be more than 20 feet long. Larger species attack and eat humans and livestock, devouring flesh and bone with their powerful jaws and jagged teeth. Crocodiles are usually more aggressive than their cousins, alligators. In parts of Africa, crocodile attacks on humans can be a regular occurrence, making them the second most dangerous animal, after hippos. Nonetheless, crocodiles do not kill large numbers of humans. Fishermen and women washing, or getting water from a riverbank, are most at risk for attack. In Florida, alligators feed at dusk, making it an inadvisable time to swim or even be near the water.


While they are reputed to be scavengers, hyenas are also skilled hunters. Attacks on humans are not unknown. Hyenas hunt in teams, often circling and wearing down much larger animals, such as wildebeests and zebras. If a hyena clan is large enough, it will challenge a pride of lions in a battle over food.

If a hyena clan is large enough, it will challenge a pride of lions in a battle over food.

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