What is the food chain of the brown bear?

The Polar Bear is at the top of the "food chain" in the Arctic. They maintain the balance of nature, by preventing an overpopulation of seals. Seals are the Polar Bear's primary food. Specifically, the Ringed Seal, and occasionally the Bearded Seal. But if hunting is good, and prey plentiful, the average adult Polar Bear, will usually only eat the fatty portions of the seal, leaving the rest for other animals, such as younger Polar Bears, or Arctic Foxes, and the Ravens. Seals are not the only thing that Polar Bears have been know to hunt. Sometimes, they both hunt and eat walrus, Beluga Whales, as well as Short-legged Reindeer, and other foods, such as birds, bird eggs, beached whales, and even kelp. For more details, please see the sites listed below.

The only thing that can beat a polar bear is a hunter, and another polar bear.

They are at the top of the food chain in their natural environment.