The Pacific Crest Trail is a 2,650-mile trail that spans the distance from Canada to Mexico. Along the trail are thousands of plant and animal species, some of which demand caution. Education is the best protection; even though the odds of encountering a venomous snake are low, it is wise to familiarize yourself with the venomous species found along the trail.
The only dangerously venomous snakes a hiker is likely to encounter on the Pacific Crest Trail are rattlesnakes. Copperheads (Agkistrodon contortrix ssp.), cottonmouths (Agkistrodon piscivorous ssp.) and coral snakes (Micrurus sp.) are not found as far west as the trail. Though a few other species found on the trail are technically venomous -- lyre snakes (Trimorphodon sp.) are one example -- their fangs are in the rear of their mouth, so they don’t represent a significant medical threat to humans.
Rattlesnakes are big-bodied, sedentary snakes with highly modified tail scales. Made of interlocking pieces that buzz when vibrated, rattlesnakes rely on this tool to dissuade predators. Primarily ambush hunters, rattlesnakes lie in wait alongside rodent and lizard pathways for their food to come to them. Rattlesnakes are highly venomous, and equipped with two large, foldable fangs in the front of their mouths. Despite this powerful defense mechanism, rattlesnakes do not seek out confrontation and will often retreat if given the chance to do so. Simply watching where you put your hands and feet will prevent most accidents. Contrary to popular belief, rattlesnakes do not always rattle before striking.
Northern Trail Sections
Two venomous snakes are found in the northern sections of the trail: the western rattlesnake (Crotalus viridis) and the Northern Pacific rattlesnake (Crotalus oreganus oreganus). The western rattlesnake is found sporadically in this area, but Northern Pacific rattlesnake specimens live alongside most of the trail. This far north, however, snakes struggle to adequately heat themselves: watch out for basking snakes in sunny but protected locations like the buttress of a tree or among rocks and boulders.
Middle Trail Sections
The Northern Pacific Rattlesnake, found almost all the way to Santa Barbara, California, is joined in Oregon by the Great Basin rattlesnake (Crotalus oreganus lutosus). Authorities debate the taxonomy of the Great Basin Rattlesnake; some still consider it to be a subspecies of the western rattlesnake (Crotalus viridis) while others consider it to be -- as it is currently recognized -- a subspecies of the Pacific rattlesnake (Crotalus oreganus).
Southern Trail Sections
As with most reptiles, diversity grows as one travels toward the equator. Colorado sidewinders (Crotalus cerastes laterorepens) join the trail first, but they are soon replaced by a different sidewinder subspecies: Mojave sidewinders (Crotalus cerastes cerastes). Panamint rattlesnakes (Crotalus stephensi), southwest speckled rattlesnakes (Crotalus mitchellii pyrrhus) and northern Mojave rattlesnakes (Crotalus scutulatus scutulatus) begin to occur as one approaches the Mohave Desert. Some authorities consider the Mojave rattlesnake to be the most dangerous rattlesnake of all, as it has a venom that acts to suppress breathing rather than causes a lot of tissue destruction like most other rattlesnakes. Eventually, the Northern Pacific rattlesnake gives way to the southern subspecies -- the Southern Pacific rattlesnake (C. oreganus helleri). Western diamondback rattlesnakes (Crotalus atrox) and the beautiful red diamond rattlesnakes (Crotalus ruber) also live in southernmost area of the Pacific Crest Trail.