Fear of predators can help restore balance to an ecosystem, even when there are no actual predators around, Pacific Standard reports. Since humans wiped out bears, wolves, and mountain lions on British Columbia’s Gulf Islands, raccoons have run rampant, decimating local crab and fish populations. The only raccoon predators that remain are dogs. When researchers played recordings of dog barks on the beach, raccoons spent less time hunting there, and crab and fish populations rebounded, the researchers reported yesterday in Nature Communications. The findings emphasize the need for large predators in ecosystems, both to kill prey and to make other creatures less brazen.