March 28, 2011 © Thomas J. Kollenborn. All Rights Reserved.
Spring
is here and reptiles, meaning most cold-blooded animals, become very
active when temperatures soar. When it warms up in the Spring it is wise
to keep a keen eye open for rattlesnakes.
August and September are
traditionally the most active months for rattlesnakes on the Sonoran
Desert at elevations below 4,000 feet. But reptiles come out of
hibernation begin the search for food as the weather warms in the Spring
of the year. In late fall when temperatures drop below seventy-eight
degrees, reptiles begin to prepare for hibernation.
I have lived in the Sonoran
Desert for more than sixty years and have encountered hundreds of
rattlesnakes. Under most conditions a rattlesnake is very difficult to
spot unless it is disturbed and it moves. Rattlesnakes generally rattle
before they move, but if the truth were really known, most people who
walk or hike in the desert will walk by ten snakes for everyone they
see.
A rattlesnake can easily be
identified by the triangular-shape of its head and the rattle on its
tail. A closer examination will reveal an elliptical-shaped pupil in its
eye. This trait is common to poisonous snakes in the Sonoran Desert.
All rattlesnakes will have a
pit organ near the nostril orifice. They come in a variety of colors and
patterns. The snakes found in our area will have rings around their
tails above the rattles. The color of these rings will alternate between
black and white in various shades. The visibility of these rings will
depend on the species. The Western Diamond Back rattler’s rings are very
pronounced and stand out, where as the rings on an Arizona Black is not
very visible because of the blending of the rings. Occasionally a
rattlesnake will lose it rattles. When this occurs, the difficulty of
identification increases.
Rattlesnakes are ectothermic
vertebrates (cold-blooded animals), meaning they lack an appropriate
physiological mechanism for maintaining body temperature. All
cold-blooded animals are at the mercy of their environment. Air and
ground temperatures dramatically affect the environment of reptiles.
This condition directly affects their daily rhythm of activity and their
habitat.
There are six species of
rattlesnakes in our area, including the Western Diamond Back (Crotalus
atrox), Mohave (Crotalus scutulatus), Arizona Black (Crotalus vidiris),
Black-Tailed (Crotalus molossos), Sidewinder (Crotalus cerastes), and
the Tiger (Crotalus tigris). These animals have a very highly developed
mechanism of injecting venom, therefore making them very successful
predators in the desert. A rattlesnake’s diet is composed of small
rodents 82% to 85% of the time.
Reptiles, including
rattlesnakes, like cool shady spots during the spring, summer and fall
months. During the winter months rattlesnakes generally go underground
and hibernate. They usually choose caves or old mine tunnels.
Occasionally dens of rattlesnakes have been accidentally uncovered by
construction equipment and hundreds of rattlesnakes are found at one
time.
Rattlesnakes have been known
to come out of hibernation if temperatures warm to 78 degrees
Fahrenheit. The functioning temperature for a rattlesnake is 72 to 78
degrees Fahrenheit and it’s effective temperature is 82 degrees
Fahrenheit to 96 Degrees Fahrenheit. The effective temperature is the
temperature at which the snake moves about and hunts for prey. Direct
exposure to heat or sunlight will kill a rattlesnake in about 10 to 15
minutes.
You might say rattlesnake
season is twelve months a year in the lower Sonoran Desert if
temperatures rise above 72 degrees Fahrenheit in the winter months.
Rattlesnakes are most commonly sighted from the first of April until
about the middle of October. These animals are primarily nocturnal and
prefer the hours after sundown and before sunrise. Most victims bitten
by rattlesnakes are generally bitten ½ hour before sundown and up to two
hours after sundown. It is estimated that 72% of all bites occur during
this period.
There are some interesting
facts about rattlesnakes. The oldest known rattlesnake in captivity, a
Western Diamond Back, was 30 years and 7 months of age. The largest
rattlesnake officially recorded was an Eastern Diamond Back (Crotalus
adamatus) at 7 feet 4 inches long. The largest Western Diamondback was
measured live at 6 feet 8 inches. There have been many wild claims about
ten to fifteen-foot rattlesnakes, but usually these are snakes were
measured after death and their skin had been stretched. The average
distance a rattlesnake can strike and effectively inject venom is
one-third of its body length.
Some 80% of all rattlesnake
bites are the results of carelessness or the handling of rattlesnakes by
older juveniles or young adults. It is now estimated some 20% of
rattlesnake bites are accidental or legitimate. About 15% of rattlesnake
bites are dry socket bites, meaning no venom was injected into the
victim. The Arizona Poison Control and other medical resources reported
some 121 venomus bites for the year 1991. These numbers have been on the
increase as our population continues to grow and more people head for
the outdoors.
How do you know a rattlesnake
has actually bitten you and did it inject venom? There are several
signs and symptoms of envenomization. First, there will be fang marks.
These fang marks can be singular, dual or even a scratch. Fang marks are
generally a very small puncture wound and a burning sensation usually
follows the injection of venom by the reptile.
A metallic or rubbery taste
in the mouth often follows a bite, but not always. The tingling of the
tongue or numbness can also occur. If a rattlesnake has injected venom
into its victim, local swelling will occur within ten minutes. The
amount of envenomization is generally indicated by the severity of edema
or swelling at fang puncture site. Nausea and weakness is often
associated with snakebite.
Black or blue discoloration
will generally appear near the site of envenomization after three to six
hours. Every snake bite victim should be treated for shock, which is a
greater threat to the victim of snakebite than the venom.
The following is the
recommended first aid for a rattlesnake bite. Call 911 immediately;
snakebite is a medical emergency. If medical help is several hours away
the following treatment is recommended. Calm and reassure the victim,
decrease the movement of the limb. Identify the snake if it is possible
without further risk of another bite. It is not recommended to use a
constricting band or tourniquet unless you are a medical professional.
Many snakebite victims have come into emergency rooms with a
constricting band, such as shoelace, completely obliterated by edema or
swelling. It is extremely important to move the victim to a medical
facility without delay.
The following are some things
we can do to prevent rattlesnake bite: When walking in the desert or in
any area known for reptile habitation, always look where you step, or
place your foot, or feet (caution should always be used at night, late
evening, and early morning). Always look where you are placing your
hands or fingers. Use extreme caution before placing your hands where
you can not see what you are touching. Always look before sitting down,
especially around or near boulders or brush. Think before defecating or
urinating in the outdoors.
I have observed a variety of
bites during the past fifty years that resulted from total lack of
common sense. Small children must be closely supervised at all times in
areas of possible snake infestation or inhabitation.
If you and your family
observe these basic rules you should be safe from snakebite. As
urbanization continues at the desert edge in Arizona the threat if
snakebite is always a reality.
Editor’s note: I would like
to thank Jude McNally and his staff, Arizona Poison Control Center,
University of Arizona, Tucson, Arizona, and Dr. Findlay E. Russell and
his enormously valuable resource “Snake Venom Poisoning” printed by
Scholium International, Inc. Great Neck, New York 11021 Note: This book
is a physician’s desk reference for snake venom poisoning.
For information call
Arizona Poison Control System 1-800-362-0101. For snake removal in
Apache Junction call Apache Junction Fire District at 982-4440.
Tom
Kollenborn directed the Snake Alert program for the Apache Junction
Unified School District for seventeen years. He attended workshops and
worked closely with the University of Arizona Poison Control Center and
Medical Center.
