Grizzly bears are primarily carnivores, meaning they mainly eat meat. Their diet consists of:
* Fish: Salmon, trout, and other fish they catch in rivers and lakes.
* Mammals: Elk, deer, caribou, moose, and smaller mammals like marmots and ground squirrels.
* Berries and other plants: They supplement their diet with berries, roots, and other vegetation, especially in the fall when they are preparing for hibernation.
Plankton are microscopic organisms that live in water. While grizzly bears might occasionally eat a few small invertebrates that live near the water's edge, they don't actively seek out or consume plankton.