Category Archives: ARE?
122.ARE BIRDS DESCENDED FROM REPTILES?
Not everybody accepts the theory of evolution, but those who do have a theory to explain how birds came to be. There are many different parts of birds that are quite specialized because they have developed the ability to fly. They became warm-blooded because warm-blooded animals can change food into energy quickly. They have feathers, not only to keep warm, but because feathers make lightweight flying surfaces. They lost their teeth, because teeth are made of heavy bone. They have developed legs that act as shock absorbers. Their eyesight is very sharp.
113.IS THE WHALE THE ONLY SEA MAMMAL?
A mammal is a warm-blooded animal whose young are born alive and fed with mother’s milk. Strangely enough, there are quite a few creatures who live in the sea who are mammals.
A zoologist groups these creatures under the name “Cetaceans.” They include the whales, the porpoises, and the dolphins. By studying their skeletons and other parts, we can determine that the ancestors of these animals lived on land in very ancient times.
112.IS THE PORPOISE A MAMMAL?
It is hard to believe that the porpoise is not a fish, but a mammal. Yet it is just as much a mammal as the cow in the fields. Porpoises, dolphins and whales form the order called “Cetacea” of the group of aquatic mammals.
Actually, dolphins belong to the whale family and porpoises are a variety of dolphins. All these animals may be given the general name of whales, or cetaceans.
