You may recognize the tactic used by the fish in today’s comic from a classic joke about running from bears.
Published in the June issue of Animal Behavior, the study by Vinícius D.L. R. Goulart and Robert J. Young started as an exercise in fish spooking. The small schooling fish had a tendency to clog up the machinery in hydroelectric dams, so scientists wanted to figure out ways to keep the fish away from the dams—for both the machines’ and the fishes’ sake. Goulart and Young were simulating various predatory threats when they noticed the selfish behavior on the part of the fish.
In large groups, individuals find safety in numbers. After all, you’re less likely to be eaten if there are others for predators to choose from. But the astyanax goes one step further by offering up a sacrificial target when threatened. You’re even less likely to be eaten if you toss your friend to the wolves.
Being a jerk is not uncommon in nature. Even slime molds try to game the system to their advantage. The lesson we learn is that humans and other organisms aren’t all that different, and perhaps the only thing we have on even the lowest protists is that we’re much better at scheming, cheating, and adapting than they are.