Mammals are the highest class of vertebrates and the female has mammary glands which secrete milk for the nourishment of young after birth. Mammals are warm-blooded and the majority of their body is covered with hair. Mammals give birth to live young (except the platypus and echidna, who lay eggs). They also have three middle ear bones.
Most mammals live solely on land, but there are several groups that have specifically evolved to exist solely in aquatic environments (dolphins and whales) one of which is the largest of all animals. Only one group has mastered the art of true flight (bats) although several have developed the ability to glide through tree tops.
Our Amazing Mammals
ANIMAL FACTS - Otters
Asian Small-clawed Otters are well suited to life in and around the waterways. They are equipped with two layers of fur and a natural body oil that coats the fur, forming a waterproof layer. The air trapped between the fur layers allows the otters' skin to remain warm and dry at any time of the year. Otters spend much of their time grooming so their fur does not lose its water-resistant qualities.