These bears are first in line for a nutritious catch.

Triggered by hormonal changes, the grizzly bears now enter a phase of hyperphagia.

This allows them to eat constantly for up to 20 hours a day, without ever feeling full.

They can consume up to 100,000 calories in a single day.

And given the abundance of salmon, they can afford to be picky.

Just like the bears in the tropics, they seek out the highest form of energy.

Selecting only the fat rich eggs, the skin and brain of the fish.

In open water, it's not always easy.

But as the salmon move further upstream, the grizzlies are here too.

Where the river narrows it will be easier to land a catch.