BROWN BEARS FATTENING ON MOTHS

     Recently I saw a television program that depicted brown bears, also known as grizzly bears, during summer, using their great strength to move loose rocks on rocky slopes of the Rocky Mountains near Yellowstone National Park in their search for gatherings of brown, one-inch-long army cutworm moths to ingest.  Those small moths are loaded with fat, which the bears need to survive the coming five winter months of no available food.  Bears need to find fatty foods, including salmon, berries, these moths and other foods to have enough fat on their bodies to survive five months without eating.  

     Probably sometime in the past, a few brown bears searching for food in summer happened upon millions of moths hiding by day under the loose rocks and began to eat them.  Mother bears passed the knowledge of when and where to find those moths to their cubs who kept up that summer tradition for who knows how many generations.

     In May and June, after pupating on the Great Plains of the United States and Canada, millions upon millions of army cutworm moths migrate up the slopes of the Rocky Mountains to sip the nectar of alpine flowers nestled and flourishing among loose rocks.  Through summer, the moths rest under the rocks by day and sip nectar at night.  But by late summer, moths that survived the daily, intense predations of brown bears migrate back to the Great Plains to lay eggs in the soil of fields, including hay and grain fields.  Farmers can be thankful that brown bears consume lots of army cutworm moths before those insects get to lay eggs on their croplands.  

     Hatching moth larvae feed on almost anything green, including grain and hay plants, which irritates farmers who own those crops.  Partly-grown army cutworm moth caterpillars overwinter in the protective ground, emerge in spring to finish developing, pupate in the ground and migrate to Rocky Mountain slopes of loose rocks to feed all summer on wildflower nectar, and help create a food chain of rain, soil, sunlight, flower nectar, moths and brown bears.

     Each brown bear, during summer in the Rocky Mountains, daily ingests thousands of army cutworm moths, which helps those bruins put on body fat that will help them survive the coming winter.  It is truly amazing how adaptable and resourceful some kinds of life can be to have food and shelter in an ever-changing environment.  And many creatures display memories to be able to know when to be where to harvest food while it is available.              

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