Answer:
A Mammal is normally defined as a warm-blooded animal with a covering of fur, skin or hair which gives birth to live young who are nourished with milk, and who are vertebrate. All mammals suckle their young, but there is a sub-group known as monotremes, which are the egg-laying mammals. This group includes just the platypus and the echidna. They are still mammals because, like all mammals, they feed their young on mothers' milk. Mammals also breathe through lungs.
Most mammals are also characterised by the following anatomical features:
- A flexible neck with seven cervical vertebrae
- Mammals also show enhanced neocortex development
- Sound is produced by the larynx (a modified region of the trachea)
- limbs are oriented vertically
- The mammalian heart has 4 chambers
- Internal temperature is generally high
- Egg development occurs in the uterus (excluding monotremata)
- They have sweat glands
- A single jaw bone
- Diaphragm
- Three bones for a middle ear
- Give birth to young alive
- Feeds milk to its young
- Has hair on its body