World Bulletin / News Desk
A small population of dolphins in Western Australia state not only use sponges to help catch fish but the rare hunting technique has been passed from mother to daughter for generations, Australian researchers said.
Sightings of dolphins carrying sponges on their snouts to protect their sensitive noses while dislodging fish and crustaceans from the rocky ocean floor has been recorded since the 1980s.
But researchers at the University of New South Wales added a new dimension to their research by using computer modelling of behaviour and genetics to estimate how long the technique, which they call "sponging", has gone on.
"What's unique about the sponging behaviour is that only about five percent of dolphins use the sponges as a tool, and it's only one maternal line," said Anna Kopps at the University of New South Wales Evolution Ecologist Research Centre.
"What's new about this study now is we've got the time perspective," she told Reuters.
Scientists believe one single female started sponging in Shark Bay, Western Australia, and all her descendants in that area learned the behaviour from their mothers.
Knowing this, and that the sponging was done 30 years ago, computer modelling allowed them to study the spread of the behaviour over the past three decades -- and then reverse the process using genetics and behaviour to figure out when it might have begun.
Ultimately, they estimated that sponging has been going on for some 180 years, or roughly eight generations of dolphins.
"It's interesting that the behaviour doesn't spread to the entire population and it doesn't go extinct either," said Kopps.
Dolphin offspring are dependent on their mothers for about four years, giving them ample time to observe and learn survival techniques. The maximum lifespan of a dolphin is about 40 years.
"We don't know if it's teaching or other forms of learning," Kopps said.
While male dolphins also learn sponging from their mothers, the study found they don't pass the technique on.
"Some males use it but not many and it will be a dead end because they don't learn from the dads," Kopps said.
A blind Muslim Microsoft engineer has unveiled an AI-powered project that helps him 'see' the world
Google is being accused of using practices aimed at preserve its market dominance
Quantum spin liquid validates theory first suggested in 1973
International Civil Aviation Organization 'recognizes that sub-orbital and outer space flights will foster new tourism and transport market'
A joint European-Russian mission aiming to search for traces of life on Mars blasted off on Monday for the start of a seven-month unmanned space journey to the Red Planet.
Scott Kelly has spent more time in space than any other American and has returned back from his mission
Administrator touts success in planetary study, deep-space experiments, aviation innovation
A man left brain-dead after an experimental drug trial in France has died, local media report.
Facebook founder to donate majority of fortune over lifetime to newly formed charity
Facebook will appeal a date privacy ruling in Belgium that forces the social media giant to stop collecting digital information about people who are non-members
Japanese, Chinese, Irish scientists win 2015 Nobel prize in medicine for malaria and parasite research
Discovery could have major implications for pursuit of life on the red planet
Lawsuit sheds light on no poaching policy at Silicon Valley’s biggest companies
Searches for oncoming storms will display information such as maps, forecasts, reminders and preparedness instructions
New service unveiled as survey finds Americans having hard time navigating smartphone etiquette