A peaceful community of yellow-bellied marmots (Marmota flaviventris) should be grateful for its outcasts. When they notice a slinking coyote or circling hawk, loners are most likely to sound the alarm and alert the colony, according to a new study of marmot social networks. Each summer since 2002, researchers have tracked the alarm calls and social behavior of tagged marmots from six colonies near the Rocky Mountain Biological Laboratory in Colorado. They jotted down each friendly encounter—nose rubs, cuddles, and playful tussles—to reconstruct the social network linking 142 of the cat-sized mountain squirrels. The researchers rated each marmot for qualities such as social influence and vulnerability based on the number and strength of its relationships. They suspected that the most socially adept animals would be first to alert their cliques to danger, but in fact, unpopular marmots whistled alarm calls most frequently, the team reports online this month in Behavioral Ecology. Socially vulnerable marmots may call out predators because they can’t rely on strong social networks for protection, the researchers speculate. But standing guard could also be a way to gain access to the in crowd.