Ridge-nosed Rattlesnake
The last species of rattlesnake to be discovered in the United States
was the Arizona ridge-nosed rattlesnake (Crotalus willardi willardi),
first known to science in 1905.
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This small, brown snake, characterized by the strong white facial
stripes and the distinctive ridge along each side of its nose, is one of
the most primitive rattlesnakes found in this country.
It appears to have changed very little from its phylogenetic ancestors
which migrated northward from the Sierra Madre in Mexico.
In Arizona, the ridge-nosed rattlesnake inhabits the moist pine-oak
canyons of the Santa Rita and Huachuca Mountains which are often grown
to alder, maple, ash and other deciduous trees. |
Generally said to inhabit the higher elevations from 5,500-9,000
feet, recent collections have been made somewhat lower in the oak juniper
community, and there are unconfirmed reports of specimens from the Patagonia
Mountains between the Huachuca and Santa Rita Mountains. These reports
may indicate that the ridge-nosed rattlesnake is not as restricted in range
and habitat as previously thought.
These findings notwithstanding, the Arizona ridge-nosed rattlesnake
is a unique relict species which is an important and irreplaceable part
of the North American natural heritage. It may be very sensitive to major
alterations of its habitat due to activities such as logging and micro-habitat
destruction by snake collectors.
In the upper montane habitats, such as pine-oak and coniferous forests,
the ridge-nosed rattlesnake is difficult to see among the leaf litter.
It is a shy species which often remains motionless rather than rattling
and revealing its presence.
If discovered, it will usually try to crawl rapidly away rather than
present a defense. If restrained, it is very adept at turning and biting.
The venom does not appear to be particularly potent and no human deaths
from its bite are recorded.