Mammals are some of the most well known animals on earth. It makes sense, because you're born into a family of mammals - every human you know is a mammal! However, mammals are also split into 3 specific groups, based on how they reproduce and give birth. The three main groups of mammals that every defender should know are...
- Placental Mammals - This group is the largest, the most well known, and yes, us humans belong to this group. Placental Mammals are carried inside their mothers until the body systems of the baby can function on their own. The name comes from the fact that the mother passes food and oxygen to the baby, through the placenta. However, it should be noted that marsupials also pass their nourishment to their offspring through placenta.
- Marsupials - Also known as pouched mammals, this is the only other mammal group to give live birth to their offspring. When marsupials give birth, the babies are very tiny and not completely developed. They then live in a pouch on the mother's belly to drink milk and continue to develop after being born. Many well known animals such as kangaroos, koalas, and opossums are all marsupials.
- Monotremes -The smallest and most unique group of the three, Monotremes are the only mammals on earth that give birth by laying eggs! And they are so rare that there are only two monotremes that exist today - the echidna, and the platypus. While these animals are still endothermic (warm blooded) like all mammals, they have a lower body temperature than other mammals.
While all mammals share the characteristics of being endothermic, vertebrates, and covered with fair or fur, if you need to know how a mammal gives birth and raises their young, these 3 are the groups to remember!