Need to determine the sex of a walrus? Try looking at their jaws
To save time in the field, researchers develop a new method for sorting walruses
Male mosaic canaries are more colorful than their female counterparts thanks to one gene
Researchers found that carotenoid pigments in female canaries' feathers break down faster than in males
A version of this article originally appeared on Knowable Magazine
Sexual rivalries are how you evolve antlers, pincers, and tusks
Male-male competition makes animals "horny" as well
When evolution's path leads to a dead end
The fossil record shows that nature doesn't always make the right choices