A group of wild dolphins living in waters along the south Australian coast near Adelaide have stunned scientists and researchers, teaching members of the group to walk on their tails — a behavior typically only seen after training in captivity.
Photo Helena Pugsley
‘Tail-walking’ is a trick that dolphins perform using their powerful tails to rise vertically from the water and drive themselves forwards or backwards.
Billie — a female bottlenose dolphin in the group — spent several weeks in captivity at a local dolphinarium in the 1980′s in a rescue effort to recover from malnutrition and sickness after being trapped in a marina lock, and may have seen other dolphins performing tail walking during her short stay.
The scientists studying the group believe that Billie may be teaching the tail-walking — a behavior never before seen in the wild — on to other females in her group as a form of ‘culture.’
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“I have observed all the local dolphins over a number of years, and have watched Billie occasionally performing tail-walks in the years since her release, sometimes in the bow wave of large ships, which is an awesome sight!” said Dr. Mike Bossley from the Whale and Dolphin Conservation Society (WDCS) in Australia, one of the scientists that’s been monitoring the group on the Port River estuary.
“About 5 years ago another female dolphin called Wave began performing the same behavior, but does so with much greater regularity than Billie. A 3rd adult female dolphin has also been seen tail-walking.”
“We can’t for the life of us work out why they do it.” Dr. Bossley added.
The scientists are attempting to figure out whether the behavior might be a form of play or communication, and whether it’s likely other members of the dolphin group will inherit the tail walking talent.
“We’re doing systematic observations now to determine if there’s something that may trigger it, but so far we haven’t found anything.”
“This indicates that they do learn from each other, which is not a surprise really, but it does also seem that they exhibit elements of what in humans we would call ‘cultural’ behavior.” said Dr Bossley.
“These are things that groups develop and are passed between individuals and that come to define those groups, such as language or dancing, and it would seem that among the Port River dolphins we may have an incipient tail-walking culture.”
Dolphins have been known to show cultural behavior, something long believed to be a quality unique to humans.
A discovery was made in Australia in May 2005 with a group of Indo-Pacific Bottlenose Dolphins depicting this cultural aspect of dolphin behavior to teach their young to use tools. The dolphins break sponges off and cover their snouts with them, thus protecting their snouts while foraging. This knowledge of how to use a tool is mainly transferred from mothers to daughters, unlike simian primates, where the knowledge is generally passed on to both sexes.
The technology to use sponges as mouth protection is not genetically inherited but a taught behavior. A similar cultural behavior was discovered amongst river dolphins in Brazil, where some male dolphins use objects such as weeds and sticks as part of a sexual display.
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“If tail-walking is a true cultural behavior, it will gradually spread through the local population, probably by being adopted by youngsters.” Dr Bossley said.
“WDCS will maintain its quiet, non-invasive observations of these enigmatic animals and continue to document the behavior of these wild, free dolphins.”
“This behavior by the Adelaide dolphins demonstrates their intelligence and is even more proof that these animals are unsuitable for confinement in captivity, where they are unable to express natural behavior or form normal social groups with other animals.” said Cathy Williamson, anti-captivity campaigner for WDCS.
Play is an important part of dolphins’ lives, and they can be observed playing with seaweed or play-fighting with other dolphins. These beautiful mammals enjoy riding waves, frequently ‘surf’ coastal swells and the bow waves of boats, and they’re also willing to playfully interact with human swimmers on occasion.
Dolphins have even been witnessed leaping above the water surface performing acrobatic figures such as the Spinner Dolphin — famous for its acrobatic displays in which they will spin longitudinally along their axis as they leap through the air — which has perplexed scientists as to the purpose for the behavior.
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