The Wildebeest Myth That Fooled America

Some things no other animal on Earth does. Other things, humans do exactly the way every animal does, following the same evolutionary logic. Behavior turns out to follow rules, the same way a kidney or a bone follows rules, and those rules rest on one simple fact: if a behavior evolved, genes had something to do with it.

Genes are rarely the single cause of a behavior. But they play a role, and that means the question "how did this behavior evolve" always leads back to genes, whether or not you can point to the exact gene involved.

Three Ideas That Explain Almost Everything

Nearly all of animal behavior, including a huge amount of human behavior, comes down to three big ideas:

Individual selection: animals act to help themselves survive and reproduce.
Kin selection: animals act to help their relatives reproduce, since relatives share genes with them.
Reciprocal altruism: animals cooperate with unrelated individuals when it pays off for both sides.

Talking about what a bat "wants" or what a tree "would like" is just shorthand. It really means: over many generations, the bats or trees that acted this way left more copies of their genes than the ones that didn't.

The Wildebeest That Wasn't a Hero

Picture an old nature documentary. A hundred thousand wildebeest reach a river full of crocodiles, and there's no way across except through the water. Suddenly, an old wildebeest pushes to the front, throws himself into the river, and the crocodiles swarm him while the herd swims safely across behind him.

For decades, the explanation given on television was that the old wildebeest sacrificed himself for the good of the herd. It sounded noble. It was also completely wrong.

Closer observation showed the old wildebeest was not volunteering at all. He was too weak to fight his way out of the crowd, so the herd pushed him to the front, and then pushed him straight into the water. He was not a hero. He was the weakest member of the group, shoved forward by everyone else.

The Idea That Had to Die First

For decades, this mistaken idea was called group selection, the belief that animals behave for the good of the group, the population, or the species. It sounded reasonable, and almost every serious scientist believed it.

It fell apart once people looked closely, because animal after animal kept behaving in ways that helped themselves, not their group. Selection does not act on groups. It acts on individuals, based on whether that individual passes copies of its genes to the next generation.

This is where individual selection comes in, made famous by the zoologist Richard Dawkins under the name "the selfish gene." Animals are not working for the good of the herd. They are working to leave as many copies of their own genes in the next generation as possible.

There's an old line from the writer Samuel Butler that captures this well: a chicken is just an egg's way of making another egg. Underneath all the complicated behavior, competition, and even things that look like unrequited love, a lot of what animals do comes down to getting another copy of themselves into the next generation. It is not survival of the fittest so much as reproduction of the fittest.

That single idea plays out differently depending on what kind of selection is at work. Under plain survival pressure, it simply means running from a predator as fast as you can. Under sexual selection, it means showing off whatever traits happen to be attractive that season, so someone is willing to mate with you and pass your genes on.

Seen this way, the old wildebeest getting shoved into the river makes perfect sense. He was not a martyr. He was the individual with the least power in the group, and the rest of the herd, each one acting in its own interest, benefited from his loss.

The Wildebeest Myth That Fooled America

Three Ideas That Explain Almost Everything

The Wildebeest That Wasn't a Hero

The Idea That Had to Die First

Further Reading