We used to think the ‘sex’ of an animal was clearly defined by its chromosomes. But it’s way more complicated than it seems.

A global study of over 1,100 species reveals an evolutionary reason why females consistently live longer than males.

In many bird species, it’s the males who live longer. The researchers found support for this idea: in 72% of mammal species, females outlived males by about 12%. Meanwhile, in 68% of bird species, ...

An international team of researchers led by scientists from the Max Planck Institute for Evolutionary Anthropology in Leipzig ...

European cuckoos lay very different eggs depending on the host species. Genetic analyses have revealed how this adaptation is inherited without leading to speciation.

Across the animal kingdom, males and females rarely live the same length of time and this difference has fascinated ...