Finally, in most stories there is only one size of mountain lion—big! As the story makes its rounds the lion never gets smaller; it invariably grows larger. Somehow the records have missed all these really big lions. Any lion which measures more than 8 feet in length and 200 pounds in weight will be an extremely large, old male in the record class. The average will be much smaller. Statistics show most lions to be 5 to 7 feet in length and 80 to 130 pounds in weight for adult females, and 6 to 8 feet in length with weights of 120 to 200 pounds for adult males. Errors in estimating the size of these big cats are easily accounted for. In the first place the lion is a long, low, sleek creature that gives an impression of being longer than it is. Too, its size is unconsciously exaggerated by many people who are impressed with its tremendous power and agility. Many of its feats of strength seem impossible for an animal so small. Lastly, its tanned hide may be available for measurement. Actually this proves nothing; hides often are stretched 2 feet or more at the time the animal is skinned, and tanning does not shrink them appreciably. None of the above is meant to detract in any way from the reputation of the mountain lion or its place in American folklore. It is the third largest predator in the Southwest, being exceeded only by the jaguar and the bear in size, and surpassing them both in agility. In the past, it has been feared and hated by those whose herds and flocks have suffered from its depredations. Their efforts to exterminate it have resulted in grave biological problems at times, but in the light of more advanced study it seems probable this big carnivore will be spared in the future to keep its rightful place in our wilder areas. The mountain lion “goes with the deer”; that is to say, its function is to keep deer in check so that they will not eat up their range and starve to death. Though at first glance such a possibility seems out of the question, this has become a serious problem in recent years. It will be further intensified as suitable deer range becomes more restricted with the advance of civilization. Another function of the mountain lion-deer relationship is to weed out the diseased and inferior individuals so that the deer herd will remain healthy and up to good physical standards. It may be argued that the same end is reached by hunting, and so it is, with one major exception. The nimrod, intent on a fine trophy head, takes the buck in the prime of life, a time when he should be sireing the herd of the future. The cougar does not consciously select its victims; it takes the most easily caught, thus leaving the wisest and healthiest survivors as breeding stock.