Still other studies, such as one by biologist Rachel Smolker, who is featured on , have examined dolphin speech patterns.
Smolker and colleague John Pepper found that young male dolphins on the prowl for mates form alliances that appear to be cemented by sound.
But while porpoises have spade- or shovel-shaped teeth, dolphin teeth are sharp and pointy, perfect for grabbing a fish, crustacean, or squid.
Like bats, many dolphins are apparently able to locate and home in on their prey using a kind of sonar, producing clicks and pulses of sound that bounce off the target.
Such stories, researchers note, may arise from the fact that dolphins do cooperate to help lift ailing relatives and newborns near the surface to breathe.
And some dolphins do push floating objects around the ocean, for reasons researchers don’t fully understand.
Most mornings, small groups of dolphins — which are well-known to residents by markings on their dorsal fins — swim in to snack on fish offered by visitors.
While the feeding is carefully regulated to prevent the dolphins from becoming overdependent on the human handouts, the practice has helped draw hundreds of animals to the Bay that aren’t frightened by people.
Some researchers, for instance, showed that dolphins can use tools — a skill that at one time only humans were believed to possess.There are places, however, where the conditions are just right for studying wild dolphins. Here, as shows, clear waters and remarkably tame dolphins have allowed researchers to get close to their subjects.For more than 30 years, the wild bottlenose dolphins have been visiting the remote beach on Shark Bay about 400 miles north of Perth. They are just a few of the nearly three dozen species of dolphin that glide through the earth’s oceans, at home in a watery world most air-breathing mammals would find hostile.Like their close relatives the porpoises, dolphins are small whales that have teeth instead of comb-like baleen.