Nsikan Akpan:

On a recent trip along the western side of the Antarctic Peninsula, passengers on an adventure cruise encountered a rare bout of mortal combat, four orcas systematically hunting a crabeater seal on an ice floe.

The whales' spy-hopped and then created waves to dislodge the seal into the water. After each successive wave, the seal struggled again and again to scoot back to safety.

Pack hunting is regarded as a highly intelligent behavior, because it requires large degrees of coordination and cooperation. The behavior was first witnessed in orcas in 1979, but since then has been primarily observed in the Antarctic, and not elsewhere.

On January 2, these orcas displayed this intelligence in spades.