Grizzly bears reach weights of 180–680 kilograms (400–1,500 pounds); the male is on average 1.8 times as heavy as the female, an example of sexual dimorphism. This dimorphism suggests that size is an important factor in male/male competition. Their coloring ranges widely across geographic areas, from blond to deep brown or black. These differences, once attributed to subspeciation, are now thought to be primarily due to the different environments these bears inhabit, particularly with regard to diet and temperature.