All mammals have certain things in common that make them a mammal and not something else.  Here are the four main mammals characteristics that they all have.

There are such big variety of mammals in the world.  Some have four legs, other have two, and some even have wings and can fly.  Most mammals live on land, but some do live in the ocean.  Despite this huge variation there are many things that we all have in common.  Here are the four main characteristics that all mammals share, making them a mammal and not a bird, reptile, or fish.

4 Mammals Characteristics

All mammals have a backbone.  In other words, all of us are vertebrates.

Mothers nurse their young when they are born.  The babies of mammals all drink milk from their mother’s mammary glands.

All mammals are warm blooded.  This simply means that all of us have the ability to make and maintain our own body heat.  The fancy term for this is endotherm.  The opposite of this is a cold-blooded animal or an ectotherm.  Reptiles are ectotherms.

All mammals have hair.  Yes, I know that for a lot of mammals it is easy to see the hair.  Even those mammals that appear hairless still have hair.  Elephants have a little bit of hair.  So do marine mammals such as dolphins.  Dolphins may not be covered in a coat of hair, but they do have some tiny hair follicles.