April 6, 2009 © Thomas J. Kollenborn. All Rights Reserved.
Spring is here early this
year. Reptiles, meaning most coldblooded animals, becom very active when
temperatures soar. August and September are traditionally the most
active months for rattlesnakes on the Sonoran Desert at elevations below
4,000 feet. In the spring reptiles come out of hibernation and begin
their search for food. In late fall when temperatures drop below
seventy-eight degrees reptiles begin to prepare for hibernation.
I have lived in the Sonoran Desert for
the past sixty years and I have encountered hundreds of rattlesnakes. If
the truth were known, most of us who walk or hike in the desert will
pass by ten snakes for everyone we see. Under most conditions a
rattlesnake is very difficult to spot unless it is disturbed and it
moves. Rattlesnakes generally rattle before they move, but not always.
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. Believe
me, I don’t usually get that close to look! This trait is common to
poisonous snakes in the Sonoran Desert.
All rattlesnakes will have a pit organ
near the nostril orifice. Rattlesnakes come in a variety of colors and
patterns. Most rattlesnakes 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 rattlers; 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 coldblooded animals are
at the mercy of their environment. The air and ground temperatures will
dramatically affects all reptiles in their environment. This condition
directly affects their daily rhythm of activity in their habitat.
There are six species of rattlesnakes in
our area. They include 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 for injecting venom therefore making them very successful
predators on 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 and 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 temperature warm up to 78 degrees Fahrenheit. The
functioning temperature for a rattlesnake is 72 degrees to 78 degrees
Fahrenheit and its effective temperature is 82 degrees 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 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 72% of all bites occur during this period.
There are some interesting facts about
rattlesnakes. The oldest known rattlesnake in captivity was 30 years and
7 months. This snake was a Western Diamond Back (Crotalus atrox). The
largest rattlesnake officially recorded was an Eastern Diamond Back
(Crotalus adamatus) at 7 feet 4 inches. 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
that were measured after death and their skin had been stretched. The
average distance a rattlesnake can strike and effectively inject venom
is approximately onethird of its body length.
Some eighty per cent 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 Center and other medical resources
reported some one hundred and twenty- one Crotalus envenomizations for
the year 1991. This statistics quadrupled in 2003. Again statistics have
almost quadrupled for 2005. These numbers continue to increase each
year as our population continues to grow and more people head for the
outdoors.
How do you know a rattlesnake has
actually bitten you and if the reptile injected 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. 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 venom
injected 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 the puncture wounds caused by the snake’s fangs after three to
six hours. Every snake bite victim should be treated for shock. Shock is
a greater threat to the victim’s survival then the actual venom of the
snake.
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. Again, watch where you
put your hands, feet and where you sit. As urbanization continues at the
desert edge in Arizona the threat if snakebite is always a reality.
Small children have become the tragic victims of snakebite in recent
years because of little or no supervision.
I have tried to be as thorough as I can
with accurate information about rattlesnakes in Arizona. It is important
to take note, the better understanding we have of reptiles, the better
chance we have of not becoming a victim of snakebite.
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. This book is a physician’s desk reference
for snake venom poisoning.
For information call Arizona Poison
Control System 1-800-362-0101. (The state legislature may not be funding
the Arizona Poison Control Center because of budget cuts this year.)
For snake removal in Apache Junction call Apache Junction Fire District
at 982-4440.
