Norih America 



between supraoculars small ; two scales between nasals 

 and in contact with rostral. 



General coloration buff, gray, brown, or reddish with 

 diamonds that are less clear-cut, often appearing dusty 

 with indistinct light edges ; belly cream to pinkish buff 

 sometimes clouded with gray. 



Average length 3 to 5i/i> feet ; maximum 7 feet. 



Distrihiition: Central Arkansas to southeastern Cali- 

 fornia southward through most of Texas into Mexico 

 to northern Veracruz and southern Sonora with an 

 isolated population in Oaxaca. Inhabits many types of 

 terrain from dry, sjjarsely wooded rocky hills to flat 

 de.sert and coastal .sand dunes. Often found in agri- 

 cultural land and near towns. Generally avoids dense 

 forest, swamps, and elevations above 5000 feet in the 

 United States but may be found up to 8,000 feet in 

 Mexico. 



Red Diamond Rattlesnake, C'rofulns nihcr ('()i>e. 



Ideiitiflcatioti : Separated from the western diamond- 

 back only by its more reddish color and minor details 

 of scalation (usually 29 rather than 2.'i scale rows at 

 midbody ; first lower labial usually divided in nili< r. un- 

 divided in alrox). 



Average length 40 to 50 inches: maximum about ."> feet. 



Figure 15. — Red Diamond Halllesnake, Cralaliis nihir. 

 Photo by Isabelle Hiuit Conant. 



lUslriliKtioii : Baja ('aUt(U'nia and .southwestern Cali- 

 fornia ; this species and C. atrnx meet only in a narrow 

 zone in extreme northeastern Baja California and ad- 

 jacent California. Red diamond rattlesnakes are largely 

 confined to rocky hillsides with scrubby vegetation but 

 at no great elevation. 



Remarks: These 3 large rattlesnakes, the red dia- 

 mond, eastern diamondback, and western diamondback. 

 are quite similar in aiipearance but differ somewhat in 

 behavior. The red diamond rattler is the most diurnal 

 of the group, although all may be active by day during 

 cooler times of the year. Western diamondbacks in the 

 northern part of tlieir range aggregate in large num- 

 bers to hibernate — a trait seen in some other species of 

 rattlesnakes as well. 



Temperament in tlie group shows much individual 

 variation. Generally the red diamond rattler is the 

 mildest mannered, the western diamondback the most 

 irritable. All may defend themselves with great vigor. 

 They sometimes raise the head and a loop <if the neck 



well above their coils to gain elevation in striking. All 

 may occasionally strike without rattling. The red dia- 

 mond rattler often hisses loudly. 



These snakes have long fangs and copious venom ; the 

 bite of an adult of any of the 3 is a serious matter. 

 The eastern and western diamondbacks cause most 

 of the snakebite fatalities in the I'nited States. Venom 

 of the red diamond ratlesnake is definitely less toxic and 

 fatalities from its bite are rare. 



Mojove Rattlesnake, Ciotdhis xoitfiihifit-s (Kenni- 

 col 1 ) . 



Idcntificutioii : Very similar to the western diamond- 

 back and prairie rattlesnakes in pattern and general 

 aiipearance. Scales on top of head between and anterior 

 to eyes large, resembling shields of most snakes: dark 

 rings on tail much narrower than light spaces between 

 them; general color often greenish or olive. 



Average length 30 to 40 inches : maximum about 4 

 feet. 



FiGUBE IC. — Mojave Rattlesnake. Cnitahift m-idtihitiis. 

 Photo bv Isabelle Hunt Conant. 



DistrihKtiiiii : West Texas norlbwesi ward to the Mo- 

 jave Desert of California and southeastward on the 

 Mexican highland. Occurs very largely in desert and 

 prairie-desert transition zone. Decidedly a lowland 

 snake in the northern part of its range: frerpients arid 

 mountain country in Mexico. 



RciiKirkti: Habits much like those of the western 

 diamondback li\U not generally so bad lemjiered. 



It is important to recognize the Mojave rattlesnake, 

 for its venom is more toxic and has a more marked 

 effect on respiration than that of any other North 

 American rattlesnake. Bites by this species oftentimes 

 show little local reaction and may not be considered 

 serious until severe resi)iratory difliculty supervenes. 



Rattlesnakes of the Crotahi^ rirhli-i complex 

 are widespread and sometimes difficult to differ- 

 entiate. However, over a largje part of their 

 range they are the only rattlesnakes present. 

 The following characteristics are helpful in iden- 

 tification : 



1. Light diagonal stripes on side of head, if 

 present, extend to behind angle of mouth; 



41 



