"New" Killer Whale Types at Risk From Antarctic Warming

Two newly identified types of killer whales that hunt prey off of Antarctic sea ice risk losing food sources to global warming and melting, according to a new study on the whales' movement patterns.

The study reveals that killer whales that feed primarily on fish that congregate under ice shelves are more or less "homebodies," sticking close to the ice, whereas seal-eating killer whales wander wide and seemingly aimlessly.

The differences in movement patterns likely correlate to differences in the whales' foraging strategies and how they interact with their prey, according to the study.

For example, fish-eating whales can stay local because the main anti-predator strategy of fish is to bunch up into schools, often under the ice shelves, according to researchers. On the other hand, the seal-eating whales chase prey with a wider range, as seals wash off of ice floes and travel farther.

Both types of killer whales tracked are heavily dependent on ice cover, according to Robert Pitman, a study co-author and marine biologist with the National Oceanic and Atmospheric Administration in La Jolla, California...