Image: Dolphin society
Richard Connor / UMass Dartmouth
Male bottlenose dolphins were found to live very complex and wide-ranging social lives.
By
updated 3/27/2012 11:59:28 PM ET 2012-03-28T03:59:28

An unprecedented open society of bottlenose dolphins has just been identified in Western Australia.

Most mammals, including humans, live in areas with boundaries. This population of dolphins, described in the latest Proceedings of the Royal Society B, has no such limits, even though dolphin relationships can be incredibly intense.

“Other mammals with complex social relationships live in a semi-closed group based on one or more reproductive females,” co-author Richard Connor told Discovery News, explaining that the groups or territories of these other animals “are defended by one or both sexes.”

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“An open society is one without such defended boundaries,” added Connor, a biology professor at UMass Dartmouth.

He and colleagues Srdan Randic, William Sherwin and Michael Krutzen examined the ranging and behavior of over 120 adult dolphins in a large study area at Shark Bay, Western Australia. They focused on males and their very complex social lives.

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Male bottlenose dolphins also were found to engage in extensive bisexuality, combined with periods of exclusive homosexuality. Male pairs, or even trios, cooperate to sequester and herd individual females during the mating season. Most males are also members of second-order alliances consisting of four to 14 males. Such relationships appear to be long-lasting, with one known seven-member group still intact after 17 years.

At first the researchers thought the dolphins lived somewhat like chimpanzees, since male bonding is strong, but in chimps can also lead to patrolling and defending community territory. But because of their open watery range, the Shark Bay dolphins may instead have ranges that overlap with those of other dolphins in the area.

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While dolphins can be aggressive, their “make love not war” lifestyle seems to be more peaceful than that of some other mammals, possibly even humans.

“We have seen precious little aggression between females,” Connor said. “It does occur and is probably less frequent and more subtle.”

As for males, even though “they are capable of serious aggression,” he said, “they don’t squabble constantly.”

Terrestrial mammals may simply be more tied to a home base or hearth, although survival can depend on mutual dependence for both humans and dolphins.

Connor and his team believe that odontocetes (dolphins and sperm whales), humans and elephants form a “big three” group in the animal kingdom, since we all have big brains, have complex social lives, can display overlapping ranges, and have a relatively low physical cost of locomotion. Elephants have the lowest cost of locomotion recorded for any terrestrial animal.

“Elephant babies can’t run or hide — they are just big steaks,” Connor explained.

It could then be that certain shared circumstances among the “big three” animals favor alliances, which could have driven big brains, social cognition and more.

NEWS: Dolphin intelligence explained

Somewhat similar pregnancies might also link the big three. Elephants endure a 22-month pregnancy. Pregnancies clearly slow human moms-to-be. The same holds true for dolphins.

Shawn Noren from the Institute of Marine Science, University of California at Santa Cruz, recently donned scuba gear and followed some pregnant female dolphins. Noren found that they “had huge protrusions where the fetus was sitting towards the back end of the body.” This caused the females to move less and more slowly, relying on their pod for protection and cooperative feeding.

Despite the open society existence, life isn’t all joy for male dolphins either.

“I work on the male dolphins, and their social lives are very intense; it seems there is constant drama,” Connor said.

“I have often thought, as I watched their complicated alliance relationships, that their social lives would be mentally and physically exhausting, and I’m glad I’m not a dolphin," he said.

© 2012 Discovery Channel

Explainer: The world’s 10 smartest animals

  • EBU

    We humans have the ability to learn, to reason and solve problems. We're self-aware, and we're also conscious of the presence, thoughts and feelings of others. We make tools and practice the art of deception. We're creative. We think abstractly. We have language and use it to express complex ideas. All of these are arguably signs of intelligence. Scientists may not agree on the best and fullest definition of intelligence — but they generally agree that humans are highly intelligent.

    Other members of the animal kingdom exhibit signs of intelligence as well, and some scientists might say the definition of animal vs. human intelligence is merely a matter of degree - a point that was brought home in 2005 when the London Zoo put "Homo sapiens" on display in the exhibit pictured here. Click ahead to learn about nine other species that stand out for their smarts.

  • Chimps are almost like us

    Tetsuro Matsuzawa  /  AP

    If we humans possess intelligence, chimpanzees must have some as well: Our genomes are at least 98 percent identical. Chimps make and use tools, hunt in organized groups and engage in acts of violence. Wild troops have distinct behaviors and customs. Field observations and lab experiments show chimps are capable of empathy, altruism and self-awareness. In the experiment pictured here, chimps performed better than humans on a number memory test.

  • Dolphins get creative

    Janet Mann  /  Georgetown University

    This dolphin in Australia uses a sponge to protect her snout when foraging on the seafloor, a tool use behavior that is passed on from mother to daughter. Scientists say that's just one sign of dolphin smarts. Other signs include distinct whistles and clicks that may serve as dolphin names, perhaps used in a type of language. A famous 1960s experiment found that a pair of dolphins entered a tizzy of creativity once they figured out their novel behaviors were rewarded with fish. Frustrated human test subjects just let out a sigh of relief when they caught on to the idea.

  • Elephants exhibit self-awareness

    AP

    The sheer size of their brains suggests that elephants must know a thing or two about the ways of the world. They have been seen consoling family members, helping other species in times of need, playing in water and communicating with one another via vibrations sensed in their feet. A crowning achievement, some researchers say, was when this female Asian elephant named Happy recognized herself in the mirror. The complex behavior is shared only with humans, great apes and dolphins.

  • Cephalopods have big brains

    Binyamin Hochner

    Are octopi, squids and cuttlefish smart? That's a matter of scientific intrigue, but such cephalopods are certainly among the brainiest invertebrates in the sea. The cephalopod brain surrounds the esophagus, but shares with the human brain features of complexity such as folded lobes and distinct regions for processing visual and tactile information. The how-smart debate swirls around deciphering observations that the creatures have a seemingly irrepressible curiosity, a disdain for boredom, an ability to learn and the capacity to use tools. The octopus pictured here exerts precise muscle control to eat.

  • Crows get crafty

    Alex Kacelnik et al.  /  University of Oxford

    Crows are crafty critters: They fashion tools from twigs, feathers and other bits of debris to snare food from hard-to-reach places. A crow named Betty, pictured here, uses a straight wire she bent into a hook to retrieve food from a tube. The birds are born with a tool-making ethic, but they hone their craft by watching their elders, a sign of higher intelligence. Ravens, a type of crow, have even been shown to manipulate the outcomes of their social interactions for added protection and more food.

  • Squirrels can be deceptive

    Gabriel Bouys  /  AFP - Getty Images file

    Is the squirrel pictured here plotting deception? Perhaps. Researchers recently reported that the rodents put on elaborate shows of deceptive caching to thwart would-be thieves. The behavior increased in a lab experiment after squirrels observed humans stealing their peanuts. The researchers called the finding a sign that squirrels can interpret intentions of others, though it could just be a case of learned behavior. Other studies have shown the critters make three-dimensional maps to recall where they cache their nuts. And squirrels in California will cover their fur in the scent of rattlesnakes to mask their own scent from predators.

  • Man's best friend

    University of Vienna

    Are dogs intelligent or just really good at basic obedience? They can learn to sit, lie down and fetch, for example, but can they read their owner's intentions? Research suggests they can at least find food in response to non-verbal cues, a type of understanding that scientists think may be akin to the human ability to understand someone else's point of view. The dog in the experiment pictured here accurately discriminated between photos of dogs and photos of landscapes — an indication the dog was able to form the concept of "dog."

  • Cats are adaptable

    Bob Pennell  /  AP

    Like dog owners, some cat owners have trained their pets to sit down, roll over and jump through hoops. Cats learn the tricks by observation and imitation, egged on with positive reinforcement. But training cats is harder than dogs. Does that mean they are less intelligent? Not necessarily. Cat experts say felines are just different. They are solitary animals, motivated by the need to survive. This has allowed them to adapt to a variety of domestic environments for at least 9,500 years - even the hoods of cars.

  • Pigs are wise ... and clean

    Paulo Whitaker  /  Reuters

    Here's the dirt on pigs: They are perhaps the smartest, cleanest domestic animals known - more so than cats and dogs, according to some experts. But pigs don't have sweat glands, so they roll around in the mud to stay cool. A sign of their cleverness came from experiments in the 1990s. Pigs were trained to move a cursor on a video screen with their snouts and used the cursor to distinguish between scribbles they knew and those they were seeing for the first time. They learned the task as quickly as chimpanzees.

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