If you want to find same-sex relationships in the animal kingdom, you don't have to search very far. About 1,500 different species, from sheep to sperm whales, from king penguins to koalas on down to kangaroo rats, have been spotted engaging in same-sex behavior.
Like humans, these animals mate, court, raise offspring and have sex in pairs of the opposite sex. And -- just like humans -- animals will also mate, court, raise offspring and have sex in male-male or female-female pairings, too.
1. Take, for example, the male zebra finch.