Class 11 Biology Animal Kingdom Class Mammalia


  • The most unique mammalian characteristic is the presence of milk producing glands (mammary glands) by which the young ones are nourished..
  • They have two pairs of limbs, adapted for walking, running, climbing etc.
  • The skin of mammals is unique in possessing hair.
  • External ears or pinnae are present.
  • Different types of teeth are present in the jaw.
  • Heart is four chambered, they are homoiothermous.
  • Respiration is by lungs.
  • Sexes are separate and fertilisation is internal, they are mostly viviparous and development is direct.


  1. Oviparous-Ornithorhynchus (Platypus)
  2. Viviparous-Macropus (Kangaroo)


Fig. Platypus


  Fig. Kangaroo



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