Mammals lie in relatively small class of animals among all six classes of animals. These are the animals that are found in every climate and region of world. These are one of the most ancient classes of animal that are present on earth about 200 million years ago. Here are some facts about mammals.
1. Definition
Mammals are defined as warm blooded animals that breathe in air and having hairs on their bodies. One more thing is that, all mammals produce milk. Except a few ones, all the mammals are land animals.
2. Groups
Mammals are classified into 21 groups. Among all these, the most common groups are rodents, bats, primates, insectivores, marsupials, aardvark, dugongs, manatees and flying lemurs.
3. Species
The exact number of mammal species is still not confirmed. However, it has been estimated that there are almost 450-5000 species of mammals.
4. Largest Mammal
The largest known mammal is blue whale that is also largest animal on the earth as well. the length of these largest mammals ranges from 66-98 feet with weight having range from 110-176 tons.
5. Smallest Mammal
The smallest known mammal is bumblebee bat. The total length of this smallest mammal is about one inch having weight not more than 2 gram.