What keeps mammals warm?

Answer 1

otaku's that see baby's falling from the sky but just before they explode grow wings go back to the stork, get sent to japan and grow up to be like the graphic designers that made junjou romantica

Answer 2

In some cases, mammals are kept warm by the hair or fur. Some mammals even have a double layer of fur.

Some mammals, such as the marine mammals, have a layer of blubber which helps to insulate them.

Mammals are warm-blooded, meaning they can regulate their body heat regardless of external circumstances. This is unlike reptiles, amphibians or fish, for example, which adopt the temperature of their surroundings.

Answer 3

This is called thermal homeostasis: the ability to keep a somewhat constant internal temperature despite outside circumstances.