Cats and dogs, elephants and bats, whales and horses, and monkeys and men belong to a zoological classification called “mammals”. Mammals are distinguished all other types of life by the fact that theif young are fed with milk from the mammary glands of the females. In most mammals the young are born fully formed, instead of hatching out of eggs as young birds do.
Mammals are also distinguished by the hair or fur they have on all or some parts of their bodies. They are warm-blooded, and they have a four-chambered heart and a diaphragm.
While most mammals live on dry land, a few, such as the whale and dolphin, live in the water. Some burrow in the ground, such as the mole and many rodents. And still others live in trees, such as monkeys and squirrels. The only mammals that can fly are the bats.
Scientists have arranged the mammals into a number of smaller divisions, or orders. The lowest of these orders, “the monotremes”, are mammals that lay eggs. The next order, “the edentates”, are toothless mammals. Then come the sea mammals. Then we find “the ungulates ’, or hoofed mammals.
The “carnivorous” mammals eat flesh. The rodents” are gnawing mammals. The “insectivores” are animals that eat insects. The highest order is “the primates”, or mammals with nails, instead of hoofs or claws. Monkeys, apes, and men are primates.
What Are The 7 Characteristics Of Mammals?
1. The presence of hair or fur.
2. Sweat glands.
3. Glands specialized to produce milk, known as mammary glands.
4. Three middle ear bones.
5. A neocortex region in the brain, which specializes in seeing and hearing.
6. Specialized teeth.
7. A four-chambered heart.