Gives birth to young ones except for Australian spiny ant-eater and duck-billed platypus which lay eggs.
Four chambered heart, breathe through lungs, warm-blooded or homeothermic.
Muscular diaphragm separating the thorax and abdomen internally.
Mammary glands secrete milk, pair of external ears and external testes contained in a scrotum.
- For example, humans, cats, dogs, mice, rabbits, cows, lions, elephants, kangaroos, whales, seals, dolphins, porpoises etc.