Killer whales live in all the oceans between the Arctic and Antarctic ice packs. Given this enormous range and their predatory lifestyle, it is not surprising that they are adaptable, with excellent memory, intelligence, and a capacity for social complexity. They tend to live in pods of fewer than 10 animals, built around a stable core of 2-3 generations of related females - mothers, daughters, sisters, and aunts. This is shown by genetic studies of pods living in the same area. Adult females without calves, and adult males, may help care for and train younger whales to hunt, especially when a reproducing female is rearing more than one offspring. Cooperation extends to hunting, and these animals are known to attack and drown larger whales by swarming them from all sides. Orcas may even beach themselves temporarily to snatch seals, or knock them off ice floes by ramming the ice. Their prey includes larger marine mammals, fish, birds, and cephalopods.

Links:
Mammal Species of the World
Click here for The American Society of Mammalogists species account