“They’ve been around a long time, they’re highly successful, certainly in terms of the geographical scope over which they live, the range of habitats from the polar seas to the tropics—it’s amazing,” he says. However, he studies them because he fears for them: “They are vulnerable to extinctions, and the populations are not very large. But that’s typical of apex predators, whether they’re killer whales or lions or tigers. They are never all that abundant, and so they are vulnerable.
