Like an undersea Facebook community, male and female bottlenose dolphins spend their days courting friends and building alliances. Two new studies show just how important these friendships are and the role they play in a dolphin's biggest game: the race to reproduce.
Male bottlenose dolphins form tight bonds with friends and allies that are as intricate and transitory as those of humans. Researchers already know, for example, that males team up as duos or trios - known as first-level alliances - so that they can mate with a female without her swimming away. (Females become fertile only every four to five years and are thus a rare prize.) But rival males will often try to steal the female, causing the duo or trio to join forces with other groups in what's known as a second-level alliance.
"There can be huge battles over a single female," says Richard Connor, an animal behaviorist at the University of Massachusetts at Dartmouth, who has been studying wild dolphins in Shark Bay, Australia, for 24 years. "A trio under attack will get help from their buddies."
Now, Connor and colleagues have found an even higher level of alliance. In the biggest fights, the team found, the second-level alliance may receive help from another group of male dolphins, forming what the researchers call a third-level alliance. Even among chimpanzees, scientists have not witnessed such sophisticated partnerships, where one group of animals receives help from another group in a fight. The need to keep track of these complex and shifting alliances may help explain why dolphins have such large brains, the researchers reported in Biology Letters.
Female bottlenose dolphins also have a strong network of female relatives and friends - and in the second study, Connor and another team of researchers found that this helps them have more calves. The research, reported in the Proceedings of the National Academy of Sciences, found that female dolphins have more calves that survive for three years if they have friends that have also raised calves to that age, when a dolphin calf usually becomes independent.
Note that the fights over females indicate that dolphins aren't necessarily nice beings. But then, who said that intelligent creatures had to be?
Mind, both dolphins and chimpanzees might be exceeded in intelligence by other species. I'd lay my bet on African grey parrots, with the cephalopods coming somewhat in behind. And you?