Class Mammalia are the highest group in the animal kingdom, comprising moles, bats, rodents, cats, monkeys, whales, horses, deer, elephants and other animals. All are covered with hair or fur and are warm blooded. The term mammal refers to mammary glands males females that supply milk for sucking young. Mammary glands are also found in males in undeveloped condition. Parental care is highly developed. The insulated body covering and complete separation of venous and arterial blood in the heart make the regulated body temperature possible. High rate of metabolism requires large food. Cerebellum and cerebrum provide high degree of co-ordination in all activities.

Various mammals live in all sorts of habitat from polar regions to the tropics, from sea to densest forests and direct deserts. Mammals inhabit all parts of the earth-land, water and air. The walrus and some seals live in the Arctic seas and ice, whales and porpoises in open sea, musk rat and otter live in fresh-water. The grasslands and forests are homes of many rodents, carnivores and hoofed animals. Population density varies with availability of food. Natural crevices, holes, rocks, holes in trees, burrows, tunnels etc., provide shelter for various mammals. Mammals also form good source of animal products industry, i.e., meat, wool and leather are obtained from them. They also provide transport and recreation.


  • Mammary glands present.
  • Body covered with hairs.
  • occipital condyles.
  • External ear or pinna present.
  • Jaws with differentiated teeth in sockets.
  • Heart 4-chambered.
  • Warm-blooded




  • Primitive, reptile-like.
  • Egg laying.

Order Monotremata

  1. Pinna absent. Cloaca present.
  2.  Teeth in young., Adults with horny beak.
  3. Confined to Australian region.
    Example :- Platypus or Duckbill (Ornithorhynchus), Spiny anteater (Tachyglossus = Echidna).


  • Extinct


  • Marsupials and placental mammals.
  •  External ear or pinna present.

Infra-class I. Metatheria

  • Pouched and viviparous.
  • With or without rudiment yolk sac placenta.

Order Marsupialia

  • Females with marsupium.
  • Uterus and vagina double.
    Example :- Didelphis, Macropus and Perameles
australia, kangaroo, outback

Infra-class II. Eutheria

  1. Placental mammals.
  2. Vagina single

Order 1. Insectivora

  • Snout long and tapered. Teeth sharp, pomted.
  • Feet usually 5-toed.
    Example :- Moles, Shrews. Talpa, Scolopus, Erinaceus and

Order 2. Dermoptera

  • Resemble flying squirrels in appearance.
  • Forelimbs equal and included with tail in a wide, thin, fur-covered parachute (patagium).
    Example :- Flying lemurs. Cynocephalus (= Galeopithicus)

Order 3. Chiroptera

  • Flying mammals.
  • Integumental flight membrane or wing comprises forelimbs, 2nd to 5th digits, hind limbs and tail in some.

Sub-order 1. Megachiroptera

      1. Sleep by day on tree branches, hanging head downwards with wings folded.
      2. Feed on fruits.
        Example :- Flying foxes (Fruit bats). Pteropus, Cynopterus.

Sub-order 2. Microchiroptera

      1. Hang by hind claws, head downwards during day.
      2. Gregarious or solitary.
        Example :- Insectivorous bats. Myotis, Desmodis and Vespertilo

Order 4. Edentata

  • Teeth reduced to molars in forepart of jaw.
  • Toes clawed.
    Example :- Sloths. Dasypus, Bradypus. Choloepus

Order 5. Pholidota

  • Body covered by large overlapping. plates with sparse hair between.
  • No teeth. Tongue slender for capturing insects.
    Example :- Scaly anteaters (Manis)

Order 6. Primates

  • Head turns readly on neck.
  • Innermost toe and thumb usually opposable.
    Example :- Monkeys, apes and man

Sub-order 1. Lemuroidea

      1. Head without snout.
      2. Some. toes. with claws, others with flat nails.
      3. Tail prehensile.
        Example :- Lemur (Nycticebus, Loris), tree shrew

Sub-order 2. Anthropoidea

      1. Cranium enlarged. Cerebral hemispheres extend over cerebellum.
      2. Eyes directed forwards. Vision binocular.
        Example :- New world and old world monkeys, apes and Man. Squirrel monkey (Saimiri), Spider monkey (Ateles), Marmoset (Callithrix), Rhesus monkey (Macacca), Baboon (Papio), Langur (Presbytis), Gibbon (Hylobates), Gorilla (Gorilla gorilla), Oranguttan, Chimpanzee (Pan troglodytes) and Man (Homo sapiens)

Order 7. Rodentia

  • Gnawing mammals. Incisors chisel-like. No canines.
  • Gap between incisors and cheek teeth.
    Example :- Squirrel (Funambulus), Black rat (Rattus rattus), White rats (Albino rats), Mouse (Mus musculus), Porcupine (Hystrix), Guinea pig (Castor)

Order 8. Lagomorpha

  • Diastema and cheek pouches present.
  • Weak temporal muscles.
    Example :- Hare (Lepus nigricolis), Rabbit (Oryctolagus ruficaudatus)

Order 9. Carnivora

Order 10. Cetacea

  • Medium to largest size. Body spindle-shaped. Head long pointed, directly joined to body. No neck.
  • Forelimbs paddle-like Digits embedded. No claws.
    Example :- Whales. Blue whale (Balaenoptera), Sperm whale (Physeter catodon), Porpoise (Phocaena), Dolphin (Jelphinus delphis)

Order 11. Sirenia

  • Body spindle-shaped, forelimbs paddle like. Hind limbs absent.
  • No pinna. Muzzle blunt, mouth small, lips fleshy.
    Example :- Dugong (Dugong dugong), Manatees (Trichechus).

Order 12. Proboscidea

  • Massive size, head large, ears broad and flat, neck short and body huge.
  • Legs pillar-like.
  • Nose and upperlip a long flexible muscular probosis with nostrils at tip.
    Example :- Elephants (Elephas indicus).

Order 13. Perissodactyla

  • Foot with odd number of toes, each ensheathed in cornified hoof. Functional axis of leg passing through middle (3rd toe).
  • Stomach simple.
    Example :- Horse (Equus), Tapirs (Tapirus), Donkey Ass (Equus asinus), Rhinoceros (Rhinoceros)

Order 14. Artiodactyla

  • Even-toed hoofed mammals. Hoofs cornified. Axis of leg between toes.
  • Antlers or horns on head. Stomach with 4 compartments.

Sub-order 1. Suifonnes

      1. Teeth 38-44. Canines enlarged as curved tusks.
      2. Limbs short.
        Example :- Peccaries, Pigs, Warthogs and Hippopotamus. Old world pig (Sus scrofa), Wart hog (Phacochoesus), New world pig (Tayassu tajacu), Hippopotamus (Hippopotamus amphibius)

Sub-order 2. Tylopoda

      1. Feet soft without hoof.
      2. Hump present.
      3. Stomach with 4 parts.
        Example :- Camels. One-humped Arabian camel (Camelus dromedarius), two-humped camel (Camelus bactrianus)

Sub-order 3. Ruminantia

      1. Intermediate between pigs and camels. 34 upper canines present.
      2. Stomach with 3 parts.
        Example :- Nilgai (Bos dophis), Buffalo (Bos bubalus), Cow (Bos Indian), Musk deer (Moschus), Chineese water deer (Hydropotes), European red deer (Odocoileus), Giraffe (Giraffa camelopardalis). Mountain sheep (Ovis canadensis), Mountain goat (Oreamnos americanus), Water buffalow (Bubalus bubalis), Antelope.
rhino, calf, horns

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