Gradually, as my non-expert eyes acclimate to the scene, I begin to see more sleek-bodied orcas. There are a few ... off the south end of Vancouver Island. What’s more, toxins and chemical ...

The pod of killer whales that showed up Thursday, Jan. 30, have only been documented less than 10 times since 1993.

a zoologist and renowned expert in orca acoustics, describes how orcas adapted to the ocean habitat. Watch the video above for the full story. Watch Listening to Orcas on The Nature of Things.

Over time, that name morphed into "killer whales." Scientists don't know whether orcas kill for fun. The marine mammals do some things, like killing and tossing dead porpoises in the air ...