The class Mammalia (the Mammals) is divided into two subclasses based on reproductive techniques: egg laying mammals (the Monotremes); and mammals which give live birth. The latter subclass is divided into two infraclasses: pouched mammals (the marsupials); and the placental mammals.

This list is, as yet, incomplete. However for reasons of space, it has been broken into two sections:

• List of placental mammals
• List of monotremes and marsupials (non-placental mammals)

See also:

• List of British mammals