Male fiddler crabs attract mates by waving comically large pincers, the same ones they use to intimidate other potential suitors. Male elk drink calcium from their very bones to grow antlers that weigh as much as coffee tables. There are countless other examples of big horns and big feathers: the African buffalo, the Striped Love Beetle, the Capra Ibex.
Isn’t there an easier way to arrange sexual relations in the animal kingdom?
Such horns and claws, according to Doug Emlen, biologist and author of Beetle Battles: A Scientist’s Journey of Adventure and Discovery, actually speak directly to the man’s physical condition and whether he’s been stressed or starved recently. A man’s condition affects insulin levels, which in turn affects posture or a really big hand.
The resulting arms race results in many losers, and they often sneak up behind the fighting boys to mate with the females. Enough of these shortcuts can ruin the hereditary advantage of having big horns, according to Emlen.
“You find evidence that these things disappear just as often as they reappear.”
This video originally appeared on Knowable Magazine, an independent journalistic venture from Annual Reviews. You can see the original here.