Brown-polar hybrid bears may be a result of climate change, herd formations help caribou avoid mosquitos, data system connects animals from different zoos for captive breeding, and fluoride keeps sharks cavity-free.

For more than 20 years, the Monterey Bay Aquarium has entertained, educated, and fascinated its nearly 2 million annual visitors with pioneering displays of realistic undersea environments.

(Airs Sunday, December 13) Shark Mountain takes viewers on a dive of a lifetime to reveal underwater creatures unlike anywhere else in the world.

(Airs Sunday, August 23) Explore a haven for some of the most extreme underwater predators.

NATURE lifts part of the veil of mystery shrouding some fascinating -- and often fearsome -- creatures in "The Secret World of Sharks and Rays."