The May grizzly cub shown in the April 8th posting shows by comparison the growth that takes place in a little over three months. Even without another grizzly in the photos the size difference is amazing. This growth is because grizzly bear milk contains up to 33 percent fat, more than that in heavy whipping cream. While whole milk just as it came from the cow contains about 3 1/2 percent milk fat. During this time the cubs alternate between nursing, grazing on sedge grass, a variety of berries and obtaining protein from under the rocks turned over on the beach.