It is the largest species of wild sheep. The North American bighorn sheep may approach comparable weights but is normally considerably outsized by the argali. Argali stand 85 to 135cm (3 to 4ft) high at the shoulder and measure 136 to 200cm (4 to 7ft) long from the head to the base of the tail. The female, or ewe is the smaller sex by a considerable margin, sometimes weighing less than half as much as the male, or ram. The ewes can weigh from 43.2 to 100kg (95 to 220lb) and the rams typically from 97 to 328kg (214 to 723lb), with a maximum reported mass of 356kg (785lb). The Pamir argali (also called Marco Polo sheep, for they were first described by that traveler), O. a. polii, is the largest race on average, regularly measuring more than 180cm (5.9ft) long without the tail, and is less sexually dimorphic in body mass than most other subspecies. The argali has relatively the shortest tail of any wild goat-antelope or sheep, with reported tail lengths of 9.5–17cm (3.7–6.7in).