Flying is really hard work. Compared to walking, swimming, or running, flying is the form of movement that takes the most energy and requires the most calories. That means that birds have had to ...

Explore the vital role of bone marrow stem cells. Learn how they drive bone remodeling, immunity, and skeletal health in this complete guide.

A new way of analysing fossils has revealed more about animals and environments of ancient times, when humans were evolving.