The human body is a machine whose many parts – from the microscopic details of our cells to our limbs, eyes, liver and brain – have been assembled in fits and starts over the four billion years of our ...

Dominant male lemurs flexibly grow their testicles when other males are around, putting them in a better position to successfully mate. In many species, dominant males have larger testes than ...

Max Telford does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their ...