It's a common (but evil) survival strategy in zombie movies: Injure somebody else and run like hell while they get eaten. But humans aren't the only bastards who do this. Some shoaling fish also use this selfish tactic when they're being chased by predators, according to new research.
Across the globe, numerous animals live in groups, mostly because it helps them find food and avoid predators. But group living is not without its own costs. There's more competition for the food you find. Plus, being in constant close quarters with other individuals increases your risk of contracting diseases.