Dec. 10, 2008 -- Female dolphins that use marine sponges to help them forage for prey spend less time socializing with others, but still produce the same number of offspring, according to new research. Researchers have long known of a bottlenose dolphin population in Western Australia's Shark Bay that use sponges as foraging tools, but they have been puzzled as to why only some of the dolphins use the sponges and why most are female. In a study published on the PLoS One Web site, the team from Washington's Georgetown University reveal how the sponge-using female dolphins spend more time foraging than other dolphins and dive for longer in deep water habitats. But despite spending less time socializing, the female dolphins that use sponges are equally successful at calving as non-sponge-using dolphins. Related Content: Project Earth: Animals Discovery News Blog: Born Animal ABC Science Online The absence of any clear advantage, or disadvantage, from sponge use might explain why the practice has not spread throughout the entire population, according to Rob Brooks of the University of New South Wales and editor of the research paper. "When there's food out there and you need to compete for it, individuals may choose their foraging strategy in a way that maximizes their own individual impact," said Brooks. The sponge-using dolphins cover their snout to help ferret out sand-burrowing prey from the sea floor. The study's authors suggest they may have adopted the technique to, "more effectively access prey in channel [deep water] habitats compared to non-tool users, thus exploiting an otherwise unused niche." Therefore the first dolphin to develop the sponge strategy would have had a clear advantage over other dolphins. Get More NewsMouse Cloned From Long-Frozen CellResearchers create a mouse from a long-frozen cell. Will the mammoth be next?'Bubble' Could Protect AstronautsScientists say a "bubble" around a Mars-bound spaceship could protect astronauts.Big Reduction of Snowmobiles in Yellowstone ProposedA new plan would cut snowmobile use by 40 percent in Yellowstone.Microbes: Fuel of the Future?A reddish South American microbe is literally breathing fuel, say scientists.DNA Links Remains to Steve FossetDNA tests on two bones found in California confirm they are those of Steve Fossett.Women Carry More Bacteria Than MenSome bacteria prefer women, suggests a new study. But why?Ancient 'Water Monster' Facing ExtinctionA foot-long salamander that was a key part of Aztec legend is threatened by extinction.Grand Canyon's Youth ConfirmedThe Grand Canyon is millions of years younger than previously thought, argue geologists.My Take: E-Voting Not User FriendlyOpinion: Electronic voting machines don't always capture the intent of voters.SLIDE SHOW: Landscapes of TerrorWhat makes a place feel scary? There are scientific explanations.At 40, Brain and Body SlowThe part of the brain in charge of motion starts a gradual slide in middle age.Spiders, Scorpions Among World's Oldest CreaturesMany creepy crawlies have been on Earth much longer than previously believed.Blood-Sucking Vampire Bats Sing DuetsWhite-winged vampire bats "harmonize" with separated roost mates. |
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