Networking for Dolphins
Baku, November 7 (AZERTAC). Like a marine mammal version of Facebook, male and female bottlenose dolphins spend their days courting friends and building alliances. Two new studies show just how important such friendships are to dolphins—and the role friends and alliances play in life`s biggest game: the race to reproduce.
Male bottlenose dolphins (Tursiops sp.) form tight bonds with friends and allies that are as intricate and devious 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 come into estrus only every 4 to 5 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 duos and trios 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, 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 report online today in Biology Letters.
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