Robert F. Clarke
Department of Biology
Kansas State Teachers College of Emporia
_THE KANSAS SCHOOL NATURALIST_
Vol. 5 No. 3 February 1959
The Kansas
School Naturalist
_Published by_
The Kansas State Teachers College of Emporia
_Prepared and Issued by_
The Department of Biology, with
the cooperation of the Division of Education
_Editor_: John Breukelman
Department of Biology
_Editorial Committee_: Ina M. Borman, Robert F. Clarke, Helen M.
Douglass, Gilbert A. Leisman, Carl W. Prophet, Dixon Smith
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_The Kansas School Naturalist_ is published in October, December,
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privileges authorized at Emporia, Kansas.
Poisonous Snakes of Kansas
by Robert F. Clarke
Many persons either do not know anything at all about the poisonous
snakes of our state or have a distorted group of misconceptions
concerning them. These misconceptions run from plain misknowledge about
the range or identification of poisonous snakes to fancifully elaborate
stories in which there may or may not be the barest thread of fact.
The prime reason that every person should know the poisonous snakes of
his region by sight and know something about their habits, distribution,
and abundance is that it will ease the mind of the average individual in
all of his outdoor pursuits. Most persons have heard so many false
stories about snakes that they develop a fear of _all_ snakes. _This
fear is unfounded!_ A person who knows what poisonous snakes he can
expect to encounter in a given area need only learn to identify these
and realize that _all other snakes_, _lizards_, _frogs_, _toads_,
_salamanders_, and _turtles_ do not have a poisonous bite, and,
therefore, he need not fear them. With a knowledge of the poisonous
snakes, a person can avoid places where these snakes might be found.
Another aspect is the _conservation_ of snakes. Too many people kill
snakes just because they happen to be snakes. This is uncalled for
destruction--a non-poisonous snake should no more be killed than a song
bird. In many cases, the harmless snakes are of direct economic value.
In general, all snakes are similar in habits. In Kansas, they retire for
the winter in places where the temperature will not get below the
freezing point. These may be in rocky ledges, beneath the soil, below
the roots of trees, or in protected places of human design, such as
grain bins, cisterns, cellars, and silos. With the warm days of spring,
the snakes emerge from their winter quarters and set about finding food
and mates. After mating, the sexes separate and each individual snake
goes its own way to forage for food for the rest of the year. Some
snakes lay eggs and others produce the young alive. There is about an
even division of these types in Kansas. The king snakes, rat snakes,
bull snakes, racers, and many smaller snakes lay eggs in early summer.
These eggs are deposited in a spot suitable for hatching, generally
beneath a rock or in the soil. When they hatch, the young fend for
themselves. In Kansas, water snakes, garter snakes, poisonous snakes,
and some smaller snakes give birth to living young in late summer or
early fall. Again, the young are on their own after birth. With the
coming of cooler weather the snakes leave their summer feeding grounds
and travel to places where they will hibernate for the winter.
MYTHS: Probably no other group of animals has had the variety and
expanse of tall tales credited to them as have the snakes. As the
stories go, there are snakes that can put their tails in their mouths
and roll downhill hoop-like, snakes that are capable of milking cows
dry, snakes that fly into pieces when struck and later reassemble into
whole snakes again, snakes that charm their prey, and others too
numerous to mention here. Some of these tales deal specifically with the
poisonous power of snakes or with snakes that are venomous. There is the
"Blow viper," whose very breath is poisonous! The butt of this fable is
the utterly harmless hog-nosed snake, pictured on Page 13. Many persons
think that the poisonous "fang" of a snake is the structure which is
frequently flicked in and out of the snake's mouth. This is really its
tongue, and is present in _all_ snakes. The "fang" is an enlarged tooth
in the upper jaw (see diagram, page 5). Four of the many untruths about
poisonous snakes are (1) rattlesnakes cannot cross a horsehair
rope--_they can_! (2) cottonmouth water moccasins cannot bite under
water--_they can_! (3) rattlesnakes always rattle before they
strike--_not always_! (4) the rattles present on the tail of a
rattlesnake indicate the snake's age--_no_, a new segment is added each
time that the skin is shed, which may occur several times during a year.
FOOD: Most of the adult poisonous snakes of Kansas consume only
warm-blooded prey, consisting primarily of small rodents: white-footed
mice, shrews, voles, and cotton rats in the fields, and house mice and
rats about human habitations. Small birds and young rabbits may be
taken, as well as occasional lizards and insects. The copperhead is more
insectivorous than the rattlesnakes, and the cottonmouth feeds upon
other creatures that inhabit the edges of waterways.
The poison of venomous snakes is not only a defensive mechanism, but
also a highly efficient food-getting device. Whereas some of the snakes
strike and hold the prey within their jaws until the poison has rendered
it helpless, others only strike and follow the trail to where the victim
falls.
In feeding, the snake does not chew its food, but swallows it whole. The
jaws are wonderfully adapted for this purpose, having the bones on each
side of the jaws attached to their mates on the other side by an elastic
ligament, and the upper and lower jaws also joined by such an
attachment. This allows the jaws to be spread apart and lowered, making
an opening capable of taking in a food item actually larger in diameter
than the snake! The teeth of both the upper and lower jaws are recurved,
pointing inward, and as each section of the jaw can work independently,
one side secures its grip while the other side moves forward. Thus, the
snake actually crawls around its food.
ABUNDANCE: The non-poisonous snakes far outnumber the poisonous kinds,
both in number of species and individuals. In the United States, there
are approximately 95 species of non-poisonous snakes and only 19 species
of poisonous ones, including 15 rattlesnakes, one copperhead, one
cottonmouth, and two coral snakes. In Kansas, there are six species of
poisonous snakes (two should hardly be counted) and 34 species of
non-poisonous snakes. Many of the non-poisonous species are common and
widespread. It is far more probable that any snake seen is non-poisonous
than poisonous.
SNAKE BITE: Venom is secreted from glands within the head, on each side
behind the eyes, causing the swollen appearance of the head in this
region. The venom travels through ducts to each of the two fangs. The
fangs are enlarged teeth in the front of the upper jaw. They are hollow,
with one end connected to the poison duct and the other end having an
opening on the front edge near the tip. The fangs are also fastened to a
moveable bone, which enables the fangs to be folded back against the
upper jaw when the mouth is shut and erected and directed forward when
the mouth is opened to strike. The power of a strike imbeds the fangs
into the skin of the victim, and muscles force venom from the glands
through the duct and hollow fang and out of the opening at the tip. The
venom causes a breakdown of the red blood corpuscles and walls of blood
vessels. It also has an effect upon the nervous system. Some snakes have
venom which is much more destructive to the nervous system. The pit
vipers have venom which is more _hemotoxic_ (destructive to blood),
whereas the coral snake, which belongs to the cobra group, has a venom
which is _neurotoxic_ (destructive to nerves).
The venom is yellowish and somewhat "thicker" than water. The amount of
poison ejected at any one strike varies from a part of a drop to 2 cubic
centimeters, depending upon size and kind of snake, and time elapsed
since last venom ejection. Various factors influence the amount of venom
which is injected into the victim, i.e., smaller snakes have smaller
fangs and less venom; strikes through clothing or footwear are less
effective.
It has been estimated that there are fewer than 50 deaths due to snake
bite in the United States in a year; most of these bites result from
imprudent handling of venomous serpents. There has been no survey of
snakebite in Kansas, but few deaths are reported annually. At times
several years have elapsed without any deaths being reported. Most
victims are less than 20 years of age and most bites occur on the hands,
feet, arms, or legs.
It should be stressed that poisonous snakes cannot be made harmless by
removing the fangs. The poison glands and ducts remain and other teeth
can still scratch the skin, allowing entrance of the venom. Also,
"reserve" fangs are normally present. These are immature fangs lying
along the upper jaw bone. At intervals a reserve fang grows down beside
a fang which has been used for some time. The old fang is shed and a new
sharp "hypodermic needle" is in position. Thus, snakes are sometimes
found with three or four fangs.
[Illustration: Skulls]
DUCT
POISON GLAND
FANG
SHEATH
TONGUE
SKULLS
NON-POISONOUS
POISONOUS
REPLACEMENT FANGS
Snake venom is used to manufacture _antivenin_, which is injected into
snakebite victims to help counteract the effects of the poison. The
venom is injected in graduated doses into horses, which build up an
immunity to the venom. Blood is withdrawn from the horse and the serum
is processed to produce antivenin.