The Elk is one of the largest species within the deer family, Cervidae, in the world, and one of the largest land mammals in North America and eastern Asia. Elk are more than twice as heavy as mule deer and have a more reddish hue to their hair coloring, as well as large, buff colored rump patches and smaller tails. Moose are larger and darker than elk; bulls have distinctively different antlers. Elk gather in herds, while moose are solitary. Elk cows average 225 to 241 kg (496 to 531 lb), stand 1.3 m (4.3 ft) at the shoulder, and are 2.1 m (6.9 ft) from nose to tail. Bulls are some 40% larger than cows at maturity, weighing an average of 320 to 331 kg (705 to 730 lb), standing 1.5 m (4.9 ft) at the shoulder and averaging 2.45 m (8.0 ft) in length.