Drawing on 36 years of data, a new study of 199 baboons in southern Kenya finds that adversity early in life can take years off the lifespan, but strong social bonds with other baboons in adulthood can help get them back. Baboons who formed stronger social bonds — measured as how often they groomed with their closest friends — added 2.2 years to their lives, no matter what hardships they faced when they were younger.