Extras

    Video thumbnail: Nature Killer Whales Attack Pod of Narwhal

    Nature

    Killer Whales Attack Pod of Narwhal

    Killer whales pin down an entire pod of narwhal in shallow water.

    Killer Whales Attack Pod of Narwhal

    Video thumbnail: Nature Invasion of the Killer Whales | Preview

    Nature

    Invasion of the Killer Whales | Preview

    Airs Wednesday, November 19, 2014 at 8:00 p.m. ET/PT. Check your local listings.

    Invasion of the Killer Whales | Preview

    Video thumbnail: Nature Polar Bears Try to Catch Salmon

    Nature

    Polar Bears Try to Catch Salmon

    Polar bears are forced to try their luck hunting salmon as arctic ice sheets dissappear.

    Polar Bears Try to Catch Salmon