One thing; NOWADAYS humans, not so much! Polar bears and walruses are the most common!
Another Answer
Natural predators include the Polar Bear and the Killer Whale. Inuit people also hunt the Narwhal, but they don't hunt for mass numbers and don't threaten the species survival.
The animal that preys on rattlesnakes is the king snake.
In the wild, the main animal that preys on bears is the gray wolf.
lizzards.
ooooooooooooooo
spider
horses, narwhals, and turtles:)
Narwhals
tigers,snakes.
Narwhals
y'know, lemurs and narwhals
narwhals
Leopard seals and killer whales.