Whale Facts
All whales (and their close relatives, dolphins and porpoises) are known as cetaceans. This term comes from “ketos,” a Greek word meaning “sea monster.” Many of the 79 different kinds of cetaceans do seem kind of scary when you first see them. Some of them are huge – the largest whales can grow to nearly 90 feet (27 meters) long, and weigh 2,000 times more than you or I. But in fact, these “monsters” of the deep are a lot like humans in many ways. Like us, cetaceans have a bony skeleton; in fact, the bones inside whale flippers look just like the bones of a human hand. Like us, cetaceans are warm-blooded; that is, the temperature of their blood remains more or less the same at all times. Like us, cetaceans give birth to live young, instead of laying eggs like fish, birds and many reptiles do. And even though cetaceans live under water, they must surface to breathe air, just like we do.
The next time you visit a farm, and see cows, horses or goats in the fields, you should think of whales. Why? Well, most scientists believe that these common farm animals are the whales’ closest relatives on land. All are though to have evolved from a common ancestor called a mesonychid, a small meat eating animal which looked a bit like a wolf. About 50 million years ago, some mesonychids began to venture into the sea in search of food. Over millions of years, they slowly adapted to life in the water. Their bodies lost their hair and became more streamlined; they developed a thick layer of insulating blubber under the skin to keep them warm in cold water; their front left were transformed into flippers, and their back legs disappeared, replaced by a powerful tail; their nostrils shifted to the top of their heads to make breathing at the ocean’s surface easier. By 25 million years ago, creatures resembling the whales of today were swimming about.
If you’ve ever tried to open your eyes when you’re swimming in a lake or a pool, you know that even on a sunny day, you can’t see very far underwater. So how do whales find their way around the oceans without bumping into things They rely on hearing rather than sight. Most cetaceans use a technique called echolocation to see things around them. The whale produces a series of sounds; the sound waves travel through the water, bounce off objects in their path, and return to the whale. Cetaceans use echoes to form a picture of their world tests have shown that dolphins, even when blindfolded, can tell the difference between wood, plastic and metal. Whales can also use sounds to communicate over long distances. Scientists believe that some whales can hear each other when they are as far as 2,000 miles apart. If we could do that, a person in New York City could talk to a friend in Mexico city without using a telephone!