From a long (and often sad) article, “Watching Whales Watching Us,” in the NY Times this week (emphasis mine):
In 2006…researchers at Mount Sinai School of Medicine analyzed the brains of two other baleen species—humpback and finback whales—as well as those of a number of toothed whales like dolphins and killer and sperm whales. The study revealed brain structures surprisingly similar to our own. Some, in fact, contained large concentrations of spindle cells—often referred to as the cells that make us human because of their link to higher cognitive functions like self-awareness, a sense of compassion and linguistic expression—with the added kick that whales evolved these same highly specialized neurons as many as 15 million years before we humans did, a stunning instance of a phenomenon biologists refer to as parallel evolution.
“In spite of the relative scarcity of information on many cetacean species,” the Mount Sinai scientists concluded in a report in the November 2006 edition of the journal The Anatomical Record, “it is important to note in this context that sperm whales, killer whales and certainly humpback whales exhibit complex social patterns that include intricate communication skills, coalition formation, cooperation, cultural transmission and tool usage.” They added that it is therefore “likely that some of these abilities” are related to the comparable complexity in the brain structures of whales and hominids.