Unlike other predators,grizzlies have diverse diets that can include up to 90% vegetation.However, maintaining a diet of plants can be difficult.In these northern latitudes, you have distinct seasons where it's really nice and green for part of the year and really cold for the other part.If you eat plants, you have almost nothing to eat for the cold part of the year.So, you either have to migrate like geese or hibernate like ground squirrels.Grizzly bears hibernate.Their behaviors are closely synchronized with the seasons.During the summer, they have to pack on enough body fat to survive the winter.Without it, they would either starve or not have enough energy to successfully produce offspring.