A five-and-a-half-inch deep-sea squid that lives a solitary life up to half a mile down in the dark waters of the Pacific Ocean is the latest addition to the hundreds of species that are known to engage in same-sex sex.

Over the years, scientists have added one creature after another to the list, making it clear that although nature may abhor a vacuum, it seems to be fine with just about everything else.

Male squid, for example, pay no attention to the sex of other squid. Understandably so. They live alone in the dark, males and females are hard to tell apart, and only occasionally do squids pass in the night. Far better to risk wasting a few million sperm than to miss out on a chance to reproduce.

This is only one among many sorts of same-sex sexual behavior. In some insect species, males engage in traumatic insemination, which is just what it sounds like, of other males and females alike. Among mammals, bottlenose dolphins and bonobos engage in lots of different kinds of sex. Male dolphins pursue sex with males and females equally, but the females show a preference for males. Bonobos pair off in all the combinations, often.