We’re taught that evolution goes like this: Everybody is trying to kill everybody else. All species are locked in an epic struggle for survival. Modern life is just an extension of that ongoing brutality, the capacity for carnage growing with every delay on your morning commute. Nature, the poet Lord Alfred Tennyson wrote, is “red in tooth and claw,” and so are we.

But contemporary biology paints a sunnier picture. Yes, life involves a struggle for survival. But also, Harvard biologist Martin Nowak likes to say, a snuggle for survival — from amoeba to zebra, cooperation makes species more adaptable and gives them a better shot at passing on their genes. It’s true whether you’re talking starches or primates.

This is a helpful reminder for us modern-day humans: Getting where you want to be isn’t just a matter of out-competing everyone, but cooperating with them, too. Organizational psychology research has made this empirically, abundantly true: In his bestseller Give and Take, Wharton professor Adam Grant chronicled the many ways helping people improves performance. In one telling example, call center workers more than doubled their revenue after hearing a 10 minute talk from a student who had benefitted from their fundraising work.

Nowak, the Harvard biologist, argues that reputation is the main reason humans have evolved to become such expert helpers — it’s the way a group ensures that the individuals within it are behaving themselves. Humans have language and names, which help reputations stick around. This only increased with the advent of social media. Few things spread faster than gossip on a groupchat, except for maybe public shaming on Twitter.

The incentive toward cooperation is baked into how we talk about “good” and “bad” reputations: the former is to be reliable, consistent and collaborative; the latter is to be inconsistent, difficult and undependable. Over the long term, Grant’s research suggests, a reputation for taking advantage of people will turn into opportunities passing you by. Since you don’t want to lose yours, reputation is a way of making sure that you act in a positive, at least somewhat altruistic way. If you act like a jerk, you’ll eventually be excluded from tribe, family or organization. No wonder being called selfish or egocentric is such an insult.

University of Basel neuroscientist Kelly Clancy continues the story of cooperation in a new essay for the science magazine Nautilus. At a mathematical level, working together allows individual animals to become greater than the sum of their parts: mice huddling together compensate for the metabolic challenge of being a tiny creature with lots of surface area relative to their bodies’ volume. Same with huddling penguins: Cold members of the crew rotate into the warm spots, so that the group as a whole can absorb Antarctic chills. The advantages of cooperation go down to super-simple forms of life, too — in lab experiments, cooperative yeast outcompete loner yeast. (Who knew they had such complex social lives.)

Cooperation, then, is one of the best ways to “relax selective forces,” as biologists technically describe it: The better you work together, the more situations you can adapt to. Biologists think that our ancestors beat out neanderthals and other hominids because of our adaptability, which stemmed from cooperation. Indeed, the hot new thing in evolutionary psychology is social baseline theory, which argues that human brains have evolved to expect to have supportive humans around them, thus making it easier to reduce risks and reach goals. If a couple members of the tribe keep watch at night, everybody else can rest, and taking down a mastodon is easier when you have comrades to cooperate with. Remember this the next time your partner or roommate asks you to take out the trash — a couple million years of natural selection would want you to pitch in.