Family: Viperidae, Pit Vipers view all from this family
Description 28-49 1/4" (71.1-125.7 cm). Greenish, yellowish, or grayish, with irregular light-edged, light-centered crossbands and sharply contrasting black tail. Individual scales are monochromatic. Scales keeled, in 27 rows.
Warning The Black-tailed is generally considered one of the less aggressive rattlesnakes, but is still a dangerous snake. Rattlesnakes, Copperheads, and Cottonmouths belong to a group of snakes known as pit vipers. These dangerous snakes have a heat-sensitive sensory organ on each side of the head that enables them to locate warm-blooded prey and strike accurately, even in the dark. The curved, hollow fangs are normally folded back along the jaw. When a pit viper strikes, the fangs rapidly swing forward and fill with venom as the mouth opens. The venom is a complex mixture of proteins that acts primarily on a victim's blood tissue. If you hear a rattlesnake shaking its rattle, back away. The snake is issuing a warning, and if the warning is ignored it may bite. There are many factors (temperature being the most important) that determine how a snake will react when confronted by a human. Venomous snakes should always be observed from a safe distance. Pit vipers are never safe to handle. Even dead ones can retain some neurological reflexes, and "road kills" have been known to bite. How to avoid and treat snakebites
Subspecies Three; 1 in our range: Northern Black-tailed Rattlesnake (C. m. molossus).
Breeding About 3-6 young, 9-12" long, are born in summer.
Habitat Most common in rocky mountainous areas; among rimrock and limestone outcrops, wooded stony canyons, chaparral, rocky streambeds; near se level to ca. 9,000' (2,750 m).
Range Arizona east to c. Texas, south through c. Mexico.
Discussion The natural history of this species has been the subject of a great deal of research recently. Using radio transmitters implanted into adult snakes, herpetologists have discovered that it is primarily a sit-and-wait predator that locates active rodent trails and positions itself for ambush, sometimes remaining in a single location for weeks. This research also revealed some of the first evidence of maternal care in snakes; young Black-tailed Rattlers remain in the company of their mother for a week or more after birth. The diet consists primarily of woodrats, ground squirrels and lizards. Record longevity is 15 1/2 years.
