Scientist John Mitani studies chimpanzees in Uganda, a country in Africa. He likes to tell the story of two male chimps named Hare and Ellington.

When Hare and Ellington went hunting, they would share food with each other. They spent days traveling through the forest together.

Their friendship lasted until Ellington's death. What happened next was surprising and sad. Hare had been an outgoing ape. But when Ellington died, Hare changed. "He just didn't want to be with anybody for several weeks," says Mitani.

Animal Pals

Friendship was once thought to be something for humans only. Scientists now know better. Animals can make friends too.

Animal friendship is not just about dogs playing together in the park. It is about making lasting bonds. It is also about sharing.

In humans, friendship has been linked to good health and longer life. Studies of animals have shown that those with friends may be in better health than those without friends. Friends keep friends healthy!

If you were studying animals, what clues would you look for to figure out if they were friends?

Underwater Pals

Dolphins are known to be friendly. People like to swim with them! Some people think the animals look like they are smiling. Could it be that the dolphins are happy because they have good buddies? Scientists say male bottlenose dolphins form friendships when they are young. A pair will stay close for years. They will swim side by side in the ocean. These two dolphins are swimming through a coral reef.

A Special Pair

Have you heard of Owen and Mzee? Two popular children's books have been written about them. Why? The animals have an unusual friendship. Owen is a young hippopotamus. Mzee is a tortoise that is more than 130 years old. They met after a huge storm separated Owen from his family. They became pals while living together at a wildlife center in Kenya. Go to owenandmzee.com to learn more.