In response to these challenges, narwhals may dive deeper into the ocean to hunt for larger or denser schools of fish, making the trade-off for easier catches more worthwhile, O’Corry-Crowe said.

One video revealed evidence of the marine mammals employing their tusks — which can measure nearly nine feet long — to hunt fish. In the video, several narwhals can be seen speeding toward ...

believe that narwhal tusks could get used to hunt fish. She notes that female narwhals, which usually don't have tusks, manage to find food just fine, so these tusks can't be essential.