One of the most interesting of these animals is the desert-rat, whose habits, seemingly intelligent and equally curious, enable him to maintain a home amid surroundings most unfavorable to his survival. He is a big, active fellow of a glossy gray color, and since he always leaves something in place of whatever he may carry off, he is often called the trade rat. Night-time is his "busy day." The house that he builds for himself is a veritable fortified castle built in up-to-date desert-rat style, under a protecting bush or rock, or beside a cactus--preferably a prickly pear. This stronghold, from four to five feet long and three feet high, is made of sticks interwoven with pieces of prickly cactus, thorny twigs, and odd bits in general--great care being taken to have most of the thorns project outward. His private quarters consist of a shallow hole burrowed under the centre of this thorn-woven pile. Access to the interior is gained by a winding passage. The only enemy that might try to thread the mazy hallway is the rattler, who by an ingenious device is deterred from even making the attempt. To keep his snakeship from intruding on domestic privacy Mr. Rat takes several strips of spiny cactus and lays them flatways across the passageway leading to his retreat. It is well known that a rattlesnake will not crawl over a prickly substance; hence a traveller when camping out at night in rattlesnake regions often surrounds his sleeping place with a horsehair rope as a safeguard against such an unwelcome intruder. Even the hungry, prowling coyote, who would make short work of the rat could he but get at him, fights shy of lacerating his paws by attempting to tear down the formidable pile. The desert-rat has a morbid desire to carry to his home any small article which he may chance to find lying around, as many a desert miner has found to his discomfiture, but he always leaves something in its place, such as a strip of cactus or a stick. For downright strategy no creature inhabiting the desert surpasses the road-runner, sometimes called the ground-cuckoo or snake-killer. Though omnivorous, this bird lives chiefly on reptiles and mollusks. It is decked in a gay plumage of coppery green, with streaks of white on the sides and a topknot of deep blue. In fleetness of foot it is said to equal the horse. Many stories are told of its surrounding a coiled sleeping rattlesnake with strips of cactus and then tantalizing its victim until, baffled in every attempt to get away, the snake finally inflicts a deadly bite on itself. Then the road-runner leisurely proceeds to devour the suicide.