The Washington Post today featured an article detailing what may be the first observed instance of culture in marine mammals. Dolphins, to be specific. Scientists have observed the females of one group of Australian dolphins wearing sea sponges as a kind of shield while they forage for food. The behavior is learned, passed down from mother to (almost exclusively) daughter, and does not appear to be genetically based. This does not, of course, preclude controversy, with other scientists remaining unconvinced that this really is a form of culturally-based behavior.