How do sharks communicate? Particularly, how would the sharks around the Farallones all know exactly when to evacuate? Scientists who are working on "shark repellent" may have an explanation.

Although no one will ever be completely certain why it occurred, many things have been learned about both species from the attack.

National Geographic filmed South African penguins in their natural habitat. One penguin turns to crime in order to furnish the nest and keep his mate happy.

Fascinating footage, our journey begins in Alaska's Katmai National Park, both inhospitable and beautiful. We observe brown bears as they hunt salmon, track the rare glacier bear, and then continue south to British Columbia on our hunt for the rare Kermode bear, also called ghost bear or spirit bear.

Our journey begins in Alaska's Katmai National Park, both inhospitable and beautiful. We observe brown bears as they hunt salmon, we track the rare glacier bear, and then we continue south to British Columbia on our hunt for the rare Kermode bear, also called ghost bear or spirit bear.

More stunning footage from Alaska shows, up close and personal, the brown bears in action - hunting for salmon and caring for their young. Enjoy!

Observe more stunning footage from Alaska of the bald eagle and the black bear. And finally catch a first glimpse of the rare glacier bear. Enjoy!

In summer, mother bears and their young cubs can be spotted on the plains near Hallo Bay in Alaska's Katmai National Park.

Young black bears need to be careful when encountering the North American porcupine. Enjoy more footage from Alaska and Princess Royal Island in British Columbia, where young raccoons are also out and about.

Catch glimpses of sockeye salmon, also called red salmon, as they make their way upstream in a migration known as the "red flood." Also included is footage of dippers, which are some of the only songbirds that search for food on the bottom of a body of water.

In order to fatten up before winter sets in, brown bears feast upon salmon migrating upstream to spawn. Enjoy!.

In this episode, we see how the bears coexist with other creatures in their environment, and also learn about the role of the bear in Tsimshian lore. Enjoy!

The salmon that make it upstream mate and then die of exhaustion. Meanwhile, many other animals are lurking and waiting to feed.

In this final installment of the series, a white Kermode bear encounters a black bear while fishing. Observe their behavior. Look and see for yourself what ensues!

Wild Sharks, a film by Sigurd Tesche, follows Professor Samuel Gruber who has been researching sharks for more than fifty years. He founded the Bimini Biological Field Station, called the Sharklab, on Bimini Island in the Bahamas.