Mammalia (Class)- Characteristics, Classification, Examples

Mammalia are a group of animal belong to phylum chordates that possesses mammary gland or breast. Also there are warm-blooded animal that produce or give birth to young ones.

General Characteristics of Mammalia (Class)

  1. The members of ClassMammalia (L. Mamma = breast) are characterized by the presence of mammary glands.
  2. They are warm blooded animals.
  3. The skin is covered by hairs.
  4. Sweat glands and sebaceous glands are present in skin.
  5. Mammary glands are present which in females produce milk for nourishing the young ones.
  6. External ear or pinna is present.
  7. Heterodont, thecodont and usually diphyodont dentition is met with in mammals.
  8. Pre-frontal, post-frontal, quadratojugal and basipterygoid bones absent in the skull.
  9. The skull is with two occipital condyles.
  10. The lower jaw is composed of a single bone, the dentary.
  11. Craniostylic jaw suspension.
  12. Usually, there are seven cervical vertebrae in mammals.
  13. Ribs are double-headed, having capitulum and a tuberculum.
  14. There are five digits in each limb, i.e., pentadactyl limbs present.
  15. Respiration is pulmonary.
  16. Diaphragm is present between abdomen and thorax.
  17. Heart is four-chambered with left aortic arch only.
  18. Red blood corpuscles (R.B.Cs.) are non-nucleated.
  19. Brain with four optic lobes and corpus callosum present in cerebrum.
  20. 12 pairs of cranial nerves are present.
  21. Middle ear with three ear ossicles. Interal ear has cochlea.
  22. Metanephric kidney is present.
  23. Males have copulatory organ, penis.
  24. Viviparous except monotremes which are egg laying. Young ones are developed attached with placenta.
  25. Parental care well-developed.
  26. Examples of mammals are :

Classification of Mammalia

Subclass 1- Prototheria

  1. External ear or pinna is absent.
  2. Teeth are absent in adult condition.
  3. A cloaca is present.
  4. Mammary glands are present, nipples are absent.
  5. Coracoid bone of pectoral girdle is large.
  6. Epipubic bones are present in the pelvic girdle.
  7. Ribs are single-headed.
  8. Tympanic bulla is absent. Lachrymals are absent.
  9. Corpus callosum is absent.
  10. Testes are abdominal.
  11. Egg laying mammals, placenta is absent.
  12. Examples: Echidna, Ornithorhynchus

Subclass 2-Theria

  1. Includes marsupial and placental mammals.
  2. External ears or pinna are present.
  3. Teeth are well developed.
  4. Cloaca is absent.
  5. Mammary gland present and with nipples.
  6. Testes descend into scrotal sacs.
  7. Urethra is common for vas deferences and urinary bladder.
  8. Viviparous animals.

Infra Class 1- Metatheria

  1. Marsupium is present in females.
  2. Mammary glands developed.
  3. Marsupial bone is present.
  4. Coracoid and interclavicle are absent.
  5. Epiphyses on vertebrae.
  6. Corpus callosum is poorly developed.
  7. Vagina and uterus are double.
  8. Placenta is absent.
  9. Viviparous
  10. Examples: Macropus, Didelphis

Infra class 2- Eutheria

  1. Marsupium is absent.
  2. Mammary glands are well-developed.
  3. Epipubic bones are absent.
  4. Ribs bears two heads (bicephalous) tuberculum and capitulum.
  5. Cloaca is absent.
  6. Corpus callosum is well-developed.
  7. Urinogenital ducts open independently of rectum.
  8. Testes in scrotal sacs.
  9. Vagina is single.
  10. Viviparous.
  11. Allantoic placenta is well-developed.
  12. Examples: All Placental mammals like Tiger, Hyaena, Human, Lion etc.

Some Examples of Mammalia (Class)

1. Ornithorhynchus

Classification of Ornithorhynchus



Found in south-eastern Australia and Tasmania, Triassic to recent.

Habits and Habitat

  1. It is found in fresh water, rivers, streams and lakes.
  2. Ornithorhynchus is well adapted to live in water.
  3. It is a bottom feeder and carnivorous, generally probes in the mud for crayfish, larvae of water insects, snails, tadpoles, worms and small fish.
  4. Active mainly in the early morning and evening, swimming and diving silently in the water in search of food.

Characteristics of Ornithorhynchus

  1. Commonly known as Duck-billed platypus.
  2. Body is beaver-like, about 60 cm. long and covered with brown fur.
  3. Snout is projected into a bill which is broad and flattened and resembles that of a duck.
  4. Teeth are absent. Horny jaws are present. Pouches are present between cheeks.
  5. It crushes the mollusk shells by horny pads.
  6. The eyes are small, external ears (pinnae) are absent.
  7. Limbs are pentadactyl with claws. Digits are webbed for swimming.
  8. Tails is short and stumpy.
  9. It lays eggs.
Duck Billed platypus (Ornithorhynchus) Diagram
Duck Billed platypus (Ornithorhynchus) Diagram

2. Macropus

Classification of Macropus


Characteristics of Macropus

  1. It is a herbivorous and terrestrial animal.
  2. Hindlimbs are highly developed and used for jumping.
  3. Forelimbs are small.
  4. Tail is prehensile.
  5. A fully developed marsupium is present in which four mammary glands are found, but only two of these are functional at a time.
  6. Pinnae are long.
  7. Head is proportionately smaller than the body.
  8. It is found in Australia, Tasmania and New Guinea.
Macropus Diagram
Macropus Diagram

3. Pteropus

Classification of Pteropus


Characteristics of Pteropus

  1. It is found in India, Sri Lanka, Africa and Australia.
  2. Mammary glands are present in females.
  3. It is truly flying mammals.
  4. The metacarpals and digits of forelimbs support the pleural skin, which forms patagium for flying.
  5. Hindlimbs are short and strong.
  6. It is an insectivorous animal.
  7. Sexes are separate. The female give birth to only young at a time.
  8. It is nocturnal animal.
Pteropus labelled diagram
Pteropus labelled diagram

4. Talpa

Classification of Talpa



It is found throughout Asia and Europe.

Habits and Habitat

  1. It is subterranean burrowing mammal, lives in tunnels dug in soil.
  2. Nocturnal and omnivorous, feeds on insects, worms, seeds etc.

Characteristics of Talpa

  1. Talpa is commonly known as Short-tailed mole.
  2. It resembles mice in body shape and measures about 15 cm. in length.
  3. The body is cylindrical and covered by soft fur.
  4. Head is short, conical with pointed snout.
  5. Eyes are very small; ears pinna is absent and tail is short.
  6. Forelimbs are well-developed, broad and provided with claws for digging.
  7. There are well-developed teeth on the jaws.
  8. It is a useful mammals as it destroys insects.
Talpa (Short tailed mole) Diagram
Talpa (Short tailed mole) Diagram

5. Funambulus

Classification of Funambulus



It is found all over the world except in the Australian continent.

Habits and Habitat

  1. It is arboreal and lives on tree.
  2. Diurnal, active and fast runner, feeds on fruits and seeds.

Characteristics of Funambulus

  1. Funambulus is commonly known as Squirrel.
  2. Body is covered with soft fur and contain 3 to 5 white and grey stripes on dorsal side.
  3. The head has several vibrissae. Eye are large.
  4. Pinnae are well-developed.
  5. Claws are sharp and pointed, adapted for gripping and climbing on trees.
  6. Incisors well-developed, chisel-like and grow throughout life.
  7. Tail bushy, used as rudder during aerial jump.
  8. It builds nests on tree, viviparous.
Funambulus (Squirrel) Diagram
Funambulus (Squirrel) Diagram

6. Hystrix

Classification of Hystrix



It is found all over Asia and Africa.

Habits and Habitat

  1. Hystrix indica is found in India, inhabiting forests, rocky hills and ravines.
  2. Burrowing, nocturnal and herbivorous, feeds on crops, plants root and vegetable.
  3. When disturbed, it rolls up and quills becomes erect for defense.

Characteristics of Hystrix

  1. Hystrix is commonly known as Porcupine.
  2. Body is covered with long erectile spines or quills which are modified hairs.
  3. The spines are solid in the middle of the body but on the tail they are expanded and hollow.
  4. A great crest of stiff and long hairs is present on the head.
  5. The eyes and pinnae are small.
  6. Tail is short and non-prehensile.
  7. The soles of the feet are smooth and toes are clawed.
  8. The tongue has scattered scales arranged in rows.
  9. The spines are offensive and the animal charges the enemy with a forward thrust.
  10. It produces grunting sounds like that of a pig.
  11. It causes much damage to crop.
Hystrix (Porcupine) Labelled Diagram
Hystrix (Porcupine) Labelled Diagram

7. Loris

Classification of Loris



It is found outside Madagascar and specially in India and Sri Lanka.

Habits and Habitat

  • Strictly arboreal, nocturnal and omnivorous, feeds on insects, lizards, tree frogs, birds and their eggs.

Characteristics of Loris

  1. The body is covered with brownish fur with silvery look.
  2. It is adapted for arboreal life.
  3. The locomotion is slow. It is found often hanging upside down on trees with the help of claws or flat nails.
  4. Eyes are closely placed and very distinct and bulging.
  5. Teeth are thecodont and heterodont.
  6. Loris shows some features that recall those of higher primates such as tympanic ring.
  7. Tail is very small and indistinct.
  8. Limbs are long.
Loris Labelled Diagram
Loris Labelled Diagram

8. Hyaena hyaena

Classification of Hyaena hyaena



Hyaena hyaena is found in India, North and North-east Africa, Kenya, West Pakistan and Afganistan.

Habits and Habitat

  • Hyaena hyaena or striped hyaena is mainly nocturnal.
  • When threated, growl and erect the manes but will rarely fight.
  • There are reporting attack larger animals and carry of children.
  • Principal food is carrion.
  • Live in abandoned burrows of other animals or in caves and dense vegetation.

Characteristics of Hyaena Hyaena

  1. Commonly known as Hyaena.
  2. Body covered with coarse hairs and has a greyish to light yellowish-brown ground color with dark brown to black markings across the neck and around the legs and with the lower legs and feet almost or quite black.
  3. Manes with long hairs along the neck and back.
Hyaena labelled diagram
Hyaena labelled diagram

9. Panthera Leo

Classification of Panthera Leo



Panthera leo is found in protected area of Africa and the Gir Forest in India.

Habits and Habitat

  • Prefers open country i.e., Savannahs and plains.
  • Mostly prey on hoofed mammals, sometimes become man eaters.

Characteristics of Panthera leo

  1. Head and body length is 1.8 to 2.4 meters, tail length is 61 to 91 cm.
  2. The usual color is tawny yellow and the male has ruff or hairs-the mane around the neck and shoulder.
  3. Lion is polygamous and breeds throughout the year.
  4. The gestation period is 92 to 113 days.
  5. Number of young is usually two or three.
Panthera Leo (Lion) Diagram
Panthera Leo (Lion) Diagram

10. Panthera tigris

Classification of Panthera tigris



Panthera tigris is found throughout China and is common in forests of India, Southern China, Peninsula, Jawa and Sumatra.

Habits and Habitat

  • Feeds on animals of all kinds and it has been known to consume crocodiles, turtles and fish during floods.
  • It bathes and takes to the water freely.
  • Active mainly in night.

Characteristics of Panthera tigris

  1. Head and body is usually 1.8 to 2.8 meters.
  2. Tail length is about 90 cm.
  3. The body is beautifully striped with black stripes on yellow background.
Panthera Tigris (Tiger) labelled diagram
Panthera Tigris (Tiger) labelled diagram

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