If you saw an animal slowly suffocating to death—and there was no hope of saving it—what would you do? This is a question faced by the researchers, veterinarians, and trained volunteers who respond to whale strandings around the world.

"Most large whales, when they come to shore, they're already dead," says Craig Harms, an aquatic animal veterinarian at North Carolina State University in Morehead City.

But the ones that strand alive and can't get back out to sea face a slow, painful death unless someone intervenes. Some groups use explosive charges to kill the animal as quickly as possible. Others use exsanguination, which involves cutting a major artery where the tail meets the body, and the animal bleeds