Class Mammalia

• Mammals show presence of mammary glands [milk producing glands].
• Mammals show presence of skin with hair.
• Mammals has two pairs of limbs for walking, burrowing, swimming or flying.
• Mammals have external ear Pinnae.
• Mammals have four Chambered Heart.
• Mammals are warm blooded [Homoiotherm].
• Mammals have a well-developed alimentary canal,
• Dentation of mammals is heterodont, Thecodont and diphyodont.
• Mammals respire through lungs.
• Sexes of mammals is separate, they have internal fertilization.
• Mammals are viviparous [except for Echidna and Platypus].

  Development is direct.