More in Common Than You Think (6/7/2008)

A USC anthropologist and a UCLA biologist compare notes and create the first book that draws comparisons between primates and cetaceans.

Did dolphins and apes develop complex societies because they have big brains or did they develop big brains because of their complex societies?

"The answer might inform us about ourselves," said Craig Stanford, a USC anthropologist and co-director of USC's Jane Goodall Research Center. "Why did we evolve big brains? That's a hard question."

Primatologist Stanford and UCLA dolphin biologist Maddalena Bearzi believe they may be closer to the answer after comparing decades of research that became the basis for the book Beautiful Minds: The Parallel Lives of Great Apes and Dolphins (Harvard University Press, 2008).

Dolphins and apes have precious little in common physically or environmentally. Dolphins, shaped like cruise missiles, don't have any arms or legs and live in the ocean. Apes look similar to humans with lots of body hair and live in the forests of Africa and Asia.

Though both are mammals, cetaceans and primates have had no common ancestor for more than 100 million years.

Yet the similarities outside their appearance and habitat are striking. Dolphins and apes: live in complex, fluid societies that feature male alliances and temporary sub-groupings centered on food sources; have highly sophisticated communications systems; exhibit cultural traditions; and have invented tools used in the quest for food.

"They evolved similar traits because of their parallel societies," Stanford said.

Stanford believes that to survive in their complex social structures, both animals needed to develop a big brain, a trait they share with humans and elephants.

Apes live in a fluid community, splitting up families and forming temporary alliances in a seemingly unstructured group as they search for fruit trees. Dolphins form temporary, fluid alliances as they search for fish to eat as well as protection from predators.

It took 17 years of research for renowned primatalogist and USC professor Jane Goodall to find a pattern in what seemed like random movement, a community structure now called fission-fusion.

It was an even more difficult task to arrive at the same findings for creatures that live underwater in territories that stretch hundreds of miles. Only recently has technology allowed Bearzi to break through in ways that made this book possible.

About 10 years ago, Stanford saw Bearzi's work profiled on CNN and was amazed to learn that dolphins divide up food much the way chimpanzees do. He contacted her to find out if there might be other parallels to that of the great apes.

What he discovered as the two compared notes over the years continued to surprise him. Stanford and Bearzi subsequently published their scholarly findings last year in the journal Contributions to Zoology.

Dolphins, for example, put sponges on the top of their beak to protect themselves from abrasive sand encountered on the bottom of the ocean while searching for food.

In recent years, researchers have seen chimpanzees create spears from branches to hunt small animals, while gorillas have used sticks to gauge water depth as they wade across swamps.

Unfortunately, dolphins and apes also share another trait. Both are endangered because of overfishing and habitat loss.

Note: This story has been adapted from a news release issued by the University of Southern California

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