What is a placental mammal?

Placental mammals are the largest group of mammals.

They are characterized by young which complete their entire development attached to a placenta within the uterus. This nourishes the animal while it develops and they emerge late in their development.

The first placental mammals developed between 163 and 157 million years ago.

This group includes some of the most well known mammals such as big cats (lion, tigers etc.), elephants, rhinos, monkeys, rats, dogs, cats and more. Even us humans are considered placental mammals.

Where can you find placental mammals?

Placental mammals are the most successful group of mammals. The over 4,000 species of placental mammal can be found on every continent on Earth. They also live in the oceans.

More on Placental Mammals

Placental mammals are associated with the placenta as they spend most of their development attached to this. Marsupials are also attached to a placenta before they are born but this cannot support their entire development like the placenta of a placental mammal can.

They are also known as the eutherians.



Mammal Fact Files