How Dolphins Swim
Dophins may be our favorite water mammal. They can swim really fast--between 20 and 25 miles per hour. Sometimes they even seem to race ships. They swim in herds, especially Blackfish, which are also called Pilot Whales, even though they are dolphins. They move through the sea in schools with several hundred dolphins, coordinating their movement so that they hop out of the water and dive back in unison. These dolphins live for up to 50 years, about twice the life expectancy of the other species. But, if the leader of a school of Blackfish goes in a dangerous direction, the whole school will follow the leader no matter what. When a dolphin dives (they can dive as far as 1,000 feet deep), they lower their heart rate and allow their lungs to collapse so that they can adjust to the increase in water pressure. They can jump out of the water as high as 20 feet. Dolphins navigate by echolocation. They emit clicks through an organ at the top of their heads called a melon. The clicks give them information back like a kind of natural sonar. This way they hear the objects that are in their way and can measure how big they are before deciding whether to change directions.
How Dolphins Communicate
Dolphins communicate by whistling and clicking. They also communicate with various types of movements. Scientists are trying to crack the code of dolphin communication and are making some progress. Dolphins are able to learn to use "artificial communication systems" with people.
How Dolphins Eat
Dophins eat fish, squid and shellfish. They always eat their prey head-first which is probably the best way to tackle a squid. River dolphins, which live in Southern Asia and South America, feed at the bottoms of the rivers, pushing their beaks under the mud to find food. River dolphins are blind.
How Dolphins Care for Their Young
Dolphins are born alive and nurse their young. It is critical for the newborn dolphin to get up to the water's surface and breathe air right after it is born. The cow (that's the term for a female dolphin--a male is a bull) dives beneath the newborn and helps guide it to the surface. Then the baby must breathe air every five seconds at first. It needs to nurse once an hour.
Unusual Dolphin Behavior
The water-squirting dolphin got its name from a very unusual habit. It propels or spits water out of its mouth in streams that go seven or eight feet away.