Grizzly Bear Hunts Salmon | How Nature Works | BBC Earth

The grizzly bear. In just a few weeks, she'll eat almost 1,500 kilograms and will almost double her body weight. Feeding on a plentiful supply of salmon, she could be up to 80% bigger than bears that don't fish. On the bank, she has three young cubs and this is their first salmon run. They're busily digging under rocks, looking for salmon eggs. But if they're to survive the winter, they must learn how to catch big fish by watching their mother. It's more difficult than it looks. And they don't have long to learn. The salmon run will be over soon and every salmon caught will increase the cubs' chances of surviving the winter. But catching fish isn't their only worry. Big males roam these shores. Unrelated to the cubs, they would kill them on sight. To eat in safety, Mum leads her cubs into the cover of trees. This is the key to how the salmon can feed the forest. A bear needs up to 60,000 calories per day, the equivalent of 550 chocolate bars. So the bears prefer to eat the brains and ovaries packed with eggs, the fattiest parts of the fish, giving them maximum calories per bite. They dump the rest on the forest floor. So many bears hunt here that before long, three tonnes of salmon can litter an area the size of a football field. The smell of fish attracts this banana slug. It looks like a banana and it can grow just as long as a banana. One of the largest slugs in the world. They're crucial decomposers in this forest and they thrive in the damp conditions, up to five per square metre.