Rats (superfamily Muroidea) have a well-studied mating system that often involves males becoming sexually satiated. This means that they literally get tapped out of sperm

In many anuran (frog and toad) species, females have a sperm-storage organ (a spermatheca) that enables them to keep sperm for long periods of time.

Menopause – why would such a strategy evolve? After all, males retain the ability to procreate until the end of their life cycles (albeit with

One of the things that fascinates me the most about sex is the fact that our own species does so many things so differently than