The otter, never plentiful in the Southwest, has become extremely rare in recent years. This is due in large part to its highly specialized habits, coupled with an inability to compete with man in the use of the few fresh water streams and lakes in the desert mountains. Yet, it has been recorded often enough in the past decade to warrant the hope that with careful management and complete protection it might increase in numbers. This is much to be desired because the otter is unique in several respects among our native mammals. This mild-mannered member of the weasel family lacks many of the fierce and blood-thirsty habits of its more ferocious relatives. It is, instead, gentle, even playful. Outstanding among these characteristics is the otter’s habit of building slides. These are probably nothing more or less than a refinement of the way otters travel through the tules and slippery mud flats, in which they spend much of their time hunting crayfish and small amphibians. The remarkable thing about the slides is that they seem to be built for one specific purpose, that of sport, an activity which ordinarily is one of the least important to most mammals. In soft or muddy places, even in soft snow, the otter slides along on its chest with head held high and forelegs trailing alongside the body. Motive power is furnished by thrusts of the hind legs. Excessive wear on the underparts is reduced by many coarse, close-set overhairs which seem to have been developed for this very purpose. The slide itself is only a narrow groove, 12 to 20 inches wide, that is worn down a steep bank to the water’s edge. The wet bodies of the otters make it smooth and slippery, and soon they are able to shoot down it with only an occasional helping kick of the hind feet. This fascinating game may go on for hours on end. The descent often is followed by a general rough and tumble in the “swimming hole.” There the action is almost too fast for the eye to follow, because few mammals can match the otter for grace and speed in the water. Aquatic as the otter is, it does not care to be always wet, and this leads to another curious institution in its way of life. Near the slide, and usually at several other places along the waterway which is frequented by a family of these delightful creatures, will be found areas several feet in diameter, located among dry tules or in tall grass, where the animals roll and thus dry themselves. These seem also to be community news centers, because usually near such areas are found the scent “posts,” where otters deposit scent from the glands common to all members of the weasel family. In otters these glands do not secrete the high-potency perfume produced by those of skunks and minks. Nevertheless, it is sufficiently “loud” to be identified with the otter.