It's a video that demonstrates one of the most fearsome aspects of how many bears eat their prey. For instance, a lion won't hesitate to eat you if he's hungry, but he (or she) will typically suffocate their prey with their jaws before trying to strip flesh from bone. The same goes for alligators, who famously grab their pray, take them underwater, and then thrash until the animal drowns or suffers a broken neck. However, bears don't give a good gosh darn if you're alive or dead; as long as their victim isn't still running around, it's grub time.
So the poor little elk cries as the bear cubs do their work. It's hard to listen to, but it's nature.
Watch the whole video below, but be warned: it is graphic, and does contain brief profanity at the beginning.