From the Atlantic:
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. "