Species ( Crotalus cerastes ) of small, nocturnal rattlesnake , found in sandy deserts of Mexico and the southwestern U.S. It is 18–30 in.
(45–75 cm) long. It has hornlike scales above its eyes and is pale tan, pinkish, or gray, with an inconspicuous spotted pattern on the back and sides. It moves by looping itself obliquely across the sand, leaving a characteristic J-shaped trail. Its venomous bite is usually not fatal to humans.