Orca

Resident, transient and offshore orcas share water and ignore each other. They differ in diet, dialect, social structure and genetics, and they do not interbreed despite the opportunity. Culture, here, has become a reproductive barrier.

Hunting techniques are taught: wave-washing seals off ice floes in Antarctica, intentional beaching in Patagonia, carousel herding in Norway. Each is local, each is learned, each is lost if the population goes.