In mammals and birds, blood from the body goes to the right side of the heart first.

The breast in male and female mammals is made the same way.

Similar processes are also likely to exist in other mammals.

Breathing by birds is very different from that in mammals.

Empathy is found in many, perhaps all, mammals, and may be essential part of our life.

Sleep has also been recorded in mammals other than humans.

In mammals, the nuclear membrane can break down within minutes, following a set of steps.

It has also been found in the domestic cat, and various wild mammals.

And the enormous number of cells in mammals make them too complex for such basic studies.

In mammals, three important discoveries shed light on this issue.