Why some animals evolved to sacrifice themselves
From headbutting muskoxen to self-sacrificing bees, evolution favors populations, not individuals.
A male musk ox can weigh up to 800 pounds and charge at speeds over 30 miles per hour. During the breeding season, these shaggy, Arctic Circle behemoths crash into each other face-first and then stab their opponents with their huge, sharp horns.
What’s more, over the course of their 10- to 12-year life-spans, a single male musk ox might rack up something like 2,100 hits to the head.
All of which begs the question, how do musk oxen survive these onslaughts without turning their brains into mush?
“People have always just assumed that animals that headbutt, like musk oxen and bighorn sheep, are somehow immune to head injuries,” says Nicole Ackermans, a neuroscientist at the Icahn