Animal stories: dolphins
All of us perhaps have seen the Hollywood movie Free Willy and been amazed by the intelligence of Willy, the dolphin and the tricks that he did. We may have watched a number of programmes on television too on dolphins. Scientists say that dolphins are the most intelligent of animals. Let’s get to know these intelligent dolphins a little better.
No one knows why dolphins push people or objects toward the shore, but they have done it many times. During World War II, a group of American airmen were stranded in a raft when two dolphins came along and pushed them toward land. Dolphins regularly help fishermen in Brazil and other places by herding fish into their nets. In return, we have immortalised dolphins on murals, jewellry, and in stories. Their intelligence and friendliness continue to intrigue us.
Dolphins often work as a team to catch fish. They first herd a school of fish into a tight group, then they circle the fish to keep them corralled. Each dolphin takes a turn swimming into the middle to feed. Sometimes, when swimming near the surface, bottlenose dolphins will whack fish with their tails to send them soaring through the air. When the fish lands in the water again, it is so stunned that it is easy to catch. Their sharp teeth are used only for grabbing — dolphins almost always turn the fish around and swallow it headfirst and whole!
Using their sonar, dolphins can tell the size, shape, speed, and direction of their prey very quickly. What they look for most often is fish and squid, but they will eat other foods as well. And while they are excellent hunters, they are not above following after fishing boats to wait for trash fish to be dumped overboard.
Baby dolphins and playpens
At birth, baby dolphins are 35 to 50 inches long and weigh 30 to 50 pounds. Their mothers are very devoted and protective. Because young dolphins can quickly swim away and get lost or attacked by sharks, their mothers keep a close eye on them all the time. If a baby strays too often, its mother will trap it between her flippers, or she may even hold it underwater for some seconds. Other female dolphins serve as ‘aunties’ to help protect the babies from danger. They will work together to form ‘playpens’ around their young by swimming in a circle. This lets the babies play together in safety.
Saltwater dolphins and porpoises live all over the world — a few are even found in polar waters. Dolphins do not migrate great distances like large whales, but some do travel hundreds of miles in search of food. Freshwater dolphins are found in only a few large rivers in Asia and South America. One of these, the Ganges River dolphin, is nearly blind and uses its long snout to probe for food along the river bottom.
In 1973, 144,000 dolphins died in fishing nets. By 1993, that number was down to 3,605. The US Marine Mammal Protection Act and other laws forced the commercial fisheries to change their fishing techniques to reduce dolphin deaths. The indigenous peoples of China, India, and the Amazon believe it is important to protect the river dolphins in their areas. With so many people admiring and caring about dolphins, there is reason to hope they will be with us for a long time to come. — Agencies