Science helps us adapt and improve. For decades, marine mammal stranding response and rehabilitation organizations in the United States have been treating and rehabilitating harbor seal pups, and releasing them back into the wild. It’s critical that during rehabilitation seals gain sufficient blubber and mass so their fat reserves can enable them to survive after they are released. Prior studies have suggested that seals with greater body mass have better odds of survival. Unfortunately, until now, there has been no nationwide assessment of the sizes at which seals are released.