The third largest land animal, the hippopotamus is one of the most dangerous, aggressive mammals on Earth. Test your knowledge of these hulking beasts with the hippopotamus quiz. See more »

If Mother Nature has a sense of humor, surely the platypus is one of her punch lines. This mammal might look funny, but one of its offensive adaptations is no laughing matter. See more »

Elephants have amazing memories and are known to hold grudges for years against those who have wronged them. So, be careful who you're calling Dumbo. See more »

If you hate slathering on sunscreen, be happy you don't have to use the mucuslike variety that hippos rely on. Although hippos produce their own sunblock, they're out of luck with towels. See more »

Cony, Coney, or Hyrax, a small, hoofed mammal of the Middle East and central Africa. See more »

Duckbill Platypus, or Duck Mole, an egg-laying mammal of Australia. Platypuses and echidnas, collectively called monotremes, are unique among mammals in that they lay eggs. See more »

Elephant, the largest land-dwelling mammal. Elephants are found in Africa and Asia, primarily in forests and savannas. See more »

Hippopotamus, (plural: hippopotamuses or hippopotami), a large animal found in tropical Africa. See more »

Pika, a small furred animal found in the high mountains of eastern Europe, Asia, and western North America. See more »

Rabbits and Hares, small, shy, furry animals that are found in nearly all parts of the world. See more »