Drones for Science: Walrus Calf Scavenged by Polar Bear

This is B-roll video collected during the fall of 2024 on the Alaskan shores of the Chukchi Sea.

USGS uses small uncrewed aerial systems, also known as drones for science, to survey walrus herds and carcasses on remote Alaskan beaches. If these large herds are disturbed by any number of factors, such as bears or low flying aircraft, the herd may rush in a panic to the safety of the sea. In that rush to safety walruses are often trampled, resulting in injury or death of dozens or even hundreds of predominantly young walruses.

To understand these trampling events and account for the loss of these walruses within the Stock Assessment process required by the Marine Mammal Protection Act, USGS is pioneering survey methods with small drones and satellite imagery.

When sea ice retreats from the Chukchi Sea, female and young walruses turn to shore to rest in large herds. While on shore, disturbances can result in deaths due to trampling. Polar bears are learning to scavenge carcasses. Here you see a walrus calf carcass that has been scavenged by a polar bear. The motion of the carcass in the surf reveals that the polar bear was able to consume most of the carcass, removing nearly all bones and meat from within the calf's pelt without having cut through the pelt at any location other than the face.