Study Finds Mother Dolphins Teach Sponging to Daughters
Posted on October 17, 2012
A group of female dolphins in in Shark Bay, Western Australia use sponges as a tool. The behavior is found only in dolphins from this particular region and nowhere else in the world. The dolphins are thought to carry the sponges to protect their snouts (rostum) when they forage for fish. A paper about the technique, called sponging, was published in PLoS One in 2008.
A new study from researchers at University of New South Wales has found that the sponging technique is passed along by dolphin mothers to dolphin daughters. The researchers say male dolphins generally don't do sponging. They prefer to socialize in packs when they hunt for fish.
Dr Anna Kopps from the UNSW Evolution and Ecology Research Centre spent four years studying the dolphins and their sponge trick. She used computer modeling of behavior and genetics to estimate that the sponging behavior has been going on in Shark Bay for eight generations. She says sponging among dolphins could have stemmed from one female dolphin that started doing it at least 180 years ago and then passed the technique down through her female descendants.
Dr. Kopps says in a release, "What they do is unique among dolphins. It appears that this technique of using a sponge has been passed on from mother to daughter dolphin for around eight generations. We were interested in how long it has been passed on because it is rare for an animal species to pass learned tool use behaviour through several generation."
Here is a very brief animation of the sponging technique from Kaiulani Creamer Shorey: