Tagged: mammal

Why do women have periods?

A handful of species on Earth share a seemingly mysterious trait: a menstrual cycle. We’re one of the select few mammals on Earth that menstruate, and we also do it more than any other...

The 3 different ways mammals give birth

All mammals share certain characteristics, like warm blood and backbones. But despite their similarities, these creatures also have many biological differences — and one of the most remarkable differences is how they give birth....