In scientific terms, two people are considered friends if they consistently prefer each other over other people. However, humans are not the only ones who form friendships. Friendships between animals are very common. How does it happen?
Chimpanzees and Siamese macaques like to hang out with partners who have similar personalities. Dolphins prefer other dolphins that find their food in a similar way. Throughout the animal kingdom, species show a predilection for interacting with relatives.
When we consider the importance of touch in relationships, we often think of romantic partners. But physical connection can be equally important for any type of relationship. Our animal counterparts show us how important physical contact can be. Rooks gently groom their friends with their beaks, while monkeys groom their friends with their hands. These behaviors are not so different from the behaviors we humans have with our friendships.
Among some animals, however, friendship rituals can seem wild. White-faced capuchins greet their best friends by sticking their fingers in their eye sockets. And male guinea baboons test their bond by caressing their genitals. Dolphins encourage closeness by exchanging calls with other dolphins far away. Their whistles can travel up to 740 meters and help preserve long-distance bonds.
Friendship evolved as a social concept because it helps us, whether we are human or not. Animals that have allies live longer and healthier lives. Helping their companions cope with challenges prolongs their lives. They offer support in times of conflict and provide protection from threats such as predators and food shortages. This can prevent injury and death.
We make friends because there is a mutual benefit in doing so. Friendship between animals is different for us. In the case of humans, the benefits may be different. A shoulder to cry on, a person to help us care for our children, or a tip about job opportunities. As whales, birds and primates demonstrate, friends help us. Without them, we are less likely to survive and thrive.