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A dog is a mammal, as you know. I'll then tell you about this very important group of the animal kingdom.
Mammals are distinguished from other animals by feeding on a milk secretion during their first life months (or life years) and the birth of live young.
Children are suckled at their mother's breast. The milk-secreting organ of a female mammal is the mamma or mamilla, these words coming respectively from the Latin words mamma and mamilla; hence the word mammal as well. The woman's mamma is usually called breast.
Mammals also distinguish from other animals by having hair or fur covering their body skin, which protects them against the environment and keeps their body temperature more or less always at the same level.
Mammals are vertebrate animals whose heart pumps the blood through the circulatory system by rhythmic contraction and dilatation. Mammals show a complete separation of the heart into two pumps that do not communicate with each other; each pump is divided into two chambers: the ventricle and the atrium.
Besides dogs and also humans, a lot more animals belong to the mammal class, which is subdivided into orders:
• The gorilla, the chimpanzee and other apes are primates; humans are also Primates.
• The mole and the hedgehog are insectivorous mammals.
• The bat is a nocturnal mammal belonging to the order Chiroptera.
• Dogs, lions, cats, bears and many other mammals are carnivores.
• The cow, the ox and the camel are hoofed mammals or ungulates usually domesticated as beasts of burden like the horse and the ass.
• The whale, the dolphin and the porpoise are marine mammals of the order Cetacea.
• Rats, mice, squirrels and rabbits are rodents; they have no canine teeth and their incisors are always growing.
• To the order Edentata (meaning toothless) belong pangolins and armadillos, known for having a leathery armor shell.
• The kangaroo and the koala are mammals whose young are carried and suckled in a pouch on the mother's belly; they are called marsupials.
• The platypus and the echidna belong to the monotremes, the only mammals that lay eggs instead of giving birth to a live young.
Orders are divided into smaller groups called families; some widely known families are: Canidae (dog family), Felidae (cats), Delphinidae (dolphins), Elephantidae (elephants), Camelidae (camels).
Click on the above pictures to learn about them.
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