A tale of inter-species interaction, told by some friendly cetaceans

There are many times that humanity could stand to learn a little something from nature.

This is one of those times.

In 2011, the behavioral ecologists Alexander Wilson and Jens Krause set out to observe sperm whales off the island of Pico, in the Azores. But as they began their research, they saw something unexpected: a dolphin -- adult, male, bottlenose -- hanging out with the pod of larger, flat-nosed cetaceans. And not just swimming with them ... but rubbing against them and nuzzling up to them and generally making very, very friendly with the much larger mammals. Who tolerated -- and in some cases reciprocated -- the apparent affection. "It really looked like they had accepted the dolphin for whatever reason," Wilson told Science magazine. "They were being very sociable."

The phenomenon of inter-species canoodling isn't common, but it's not entirely rare, either. Scientists have observed other instances of "friendly" relationships among members of different species. Koko, the sign-language-adept gorilla, famously and adorably had a pet cat named All Ball; less famously, but equally adorably, a Kenyan nature park hosted the friendship between a hippopotamus named Owen and a giant tortoise named Mzee. (Many species are also brought together, of course, through the metaecological phenomenon that is YouTube.) The alliances sometimes form for -- best we can tell -- purposes of shared protection, or to practice more efficient hunting or foraging. But they might also exist, scientists speculate, for more broadly social purposes.