“Sponging” is a technique used by bottlenose dolphins to protect their noses while foraging. They carry a sponge on their nose to prevent any damage to it while dislodging fish or crustaceans from the rocky ocean floor. This behavior has been recorded since the 1980s.
Researchers from the University of New South Wales studied bottlenose dolphins in Shark Bay, Australia, and found that sponging has been around for much longer because the technique has been passed down for generations, from mother to offspring.
“What’s unique about the sponging behavior is that only about five percent of dolphins use the sponges as a tool, and it’s only one maternal line,” explained Dr. Anna Kopps, a biologist at the University of New South Wales.
Researchers believe that it was started by one female in a single “innovation event” and was passed on to her descendants in the area. Young dolphins stay with their mothers for about four years, giving them plenty of time to learn important behavior. Males also learn sponging, but they do not pass it on.
The researchers found that this behavior may have existed for up to 180 years in Shark Bay. Kopps explained that “we were interested in how long it has been passed on because it is rare for an animal species to pass learned tool use behavior through several generations.”
“It’s interesting that the behavior doesn’t spread to the entire population and it doesn’t go extinct either,” said Kopps.
To learn more:
- Read the press release from the university: Keeping it in the family
- Check out this article from BBCNature: Dolphin ‘sponging’ spans centuries
- Find the results, published in the journal Animal Behavior, here: Modelling the emergence and stability of a vertically transmitted cultural trait in bottlenose dolphins
Copyright © 2012 by Marine Science Today, a publication of Marine Science Today LLC.