Scientists have been scratching their heads over hundreds of baby whales that perished off the coast of Argentina between 2013 and 2014, but a new study points the finger at a possible cause, or at least a contributing factor: pesky seagulls, Live Science reports. The study published in PLoS One says that kelp gulls off the Peninsula Valdes that have been feasting off the skin and blubber of mother southern right whales since at least the 1970s have become increasingly aggressive over the years and turned their attention to the babies. The gulls used to be more subtle: Decades ago, the birds would simply hover over the water, waiting for whales to breach, then snack on the dead skin that sloughed off onto the water's surface. But they got brave enough to just latch onto the whales and peck away, making holes that grew bigger on each whale as time went by.
Per the study, 2% of living mothers and calves had gull lesions in the '70s; three decades later, 99% did. The mother whales wised up and started keeping their backs underwater, but the gulls then went after the little ones. "The zero- to three-month-old calves don't know how to keep their backs underwater," a study author tells Live Science. "Their backs are too small to arch, and now the gulls' primary targets are the newborn calves." The study documented one calf that had lesions on 19% of its back. Scientists note that even if the wounds themselves aren't causing the baby whales to drop off, fending off the constant attacks could take time away from nursing and playing (crucial skills) and affect how the infants fight off infection, dehydration, and other maladies—which could impact their mortality overall, per Live Science. (This whale photo, however, contained great news for scientists.)