The southwestern desert regions are credited with harboring several
genera of snakes whose grooved back teeth indicate that they may have
poisonous properties. Of these, the Sonora lyre snake[11] (_Trimorphodon
lambda_) and the Mexican vine snake (_Oxybelis aeneus auratus_) are the
only species of sufficient size to be considered as even remotely
dangerous to mankind. Species of the genera _Tantilla_ (black-headed
snake), _Hypsiglena_, and _Sonora_ are too small and too difficult for
the amateur to identify to be considered in this publication.
Gila monster
(_Heloderma suspectum_)
More conflicting statements are made about the Gila (HEE-lah) monster
than about any other desert reptile. Some persons insist that it is not
poisonous, others are sure that even its breath is poisonous: that it
spits or blows its poison: that the animal has no anal opening, hence
undigested fecal matter remains in the body, decays, and is the basis of
its poison; and so on.
[Illustration: _Gila monster_ (Heloderma suspectum).]
Here are the facts. The lizard is poisonous and its bite may be serious,
possibly fatal[13]. Its breath is not poisonous, and although the animal
seems to have a chronic case of halitosis, this has nothing to do with
its dangerous properties. It does not spit poison, but when angered it
frequently hisses, the outcoming blast of air sometimes carrying
droplets of saliva. It has a normal anal opening and voids fecal matter
in a perfectly normal manner. It is not a walking septic tank as many
persons believe.
Largest of the lizards native to the United States, and the only species
found in this country which is poisonous, the Gila monster rarely
attains a length of 2 feet. Average specimens are smaller. Its beady
skin, heavy body, short legs, and waddling gait set it apart from all
other lizards except its close relative, the also poisonous _Heloderma
horridum_ of Mexico. The Gila Monster is a spectacular black and corral
color, while the other is black and yellow.
Gila monsters are found in southern Arizona, their range extending
northwestward into the southern tip of Nevada and southwestern Utah.
[Illustration: _Underside of Gila monster showing anal opening. This
photograph is advanced as proof that the Gila monster is a perfectly
normal creature in this respect._
(Photo courtesy of Poisonous Animals Research Laboratory, Tempe,
Arizona)]
_Food and habits_
Food consists chiefly of bird and reptile eggs, young rodents, and such
small or juvenile creatures as it is able to capture. It is especially
fond of hen eggs and may be kept in captivity for a long time without
other food. It is also fond of clear water, which seems strange because
of the scarcity of this liquid in the natural habitat of the lizard. If
provided with a basin of water it may lie partly submerged for hours.
Occasionally encountered ambling across stretches of open desert,
especially in the spring, the Gila monster is normally docile and bends
every effort toward escape among the stiff stems of some bush or beneath
the protecting spine-clad stems of a cactus plant. Sometimes an
individual with a “chip on its shoulder” may be met, or one in a normal
state of mind may be teased or prodded into anger, when it advances with
open mouth, sputtering and hissing.
When aroused, the Gila monster is remarkably agile, making quick turns
of its head to snap at nearby objects. If it secures a grip, it hangs on
with bulldog-like tenacity, grinding the object between its teeth.
Gila monsters reproduce by means of eggs which are about 2½ inches long
with a tough, parchment-like skin. From 5 to 13 eggs are deposited by
the female in a hole which she scoops in moist sand in a sunny location.
After laying the eggs, she covers them with sand, and leaves them for
the heat of the sun to hatch.
[Illustration: _Poison mechanism of the Gila monster_
Redrawn from Dr. Fox]
1. Poison gland.
2. Grooved tooth.
3. Poison duct.
4. Opening, poison duct.
5. Eye.
6. Dissected lower jaw.
The Gila monster’s tail serves as a storehouse of nourishment, being
thick and heavy in times of plenty, and thin and rope-like in the early
spring when the reptile first appears after months of hibernation,
during which time it has lived on the reservoir of fat stored in its
tail.
_Poison of the Gila monster_
The poison of the Gila monster is produced by glands in the lower jaw.
To be most effective, the poison must be ground into the wound through
action of the grooved teeth, the process taking a little time. Bitten
persons who immediately have broken away sometimes show no effects of
the venom, therein lying the basis for the widespread statement that
Gila monsters are not poisonous.
Bitten persons who have been unable to release themselves show symptoms
of poisoning similar to persons suffering from rattlesnake bite,
although the poison is more neurotoxic in action. Breathing and heart
action are speeded up, followed by a gradual paralysis of the heart and
breathing muscles.
_Treatment is essentially the same as that for rattlesnake bite, which
is described earlier in this booklet. A physician should be summoned at
once. Stimulants are dangerous, and no one should be permitted to give
the patient any alcohol whatever._
Prevention is much simpler than cure, so Gila monsters should be allowed
to mind their own affairs unmolested. Normally they are not pugnacious,
and it would be very difficult for one to bite a human unless it were
being teased or handled or were stepped upon by a bare-footed child.
Please do not kill or capture Gila monsters. These interesting lizards
are a unique feature of native desert wildlife threatened with
extinction. Please leave them for other people to see and enjoy.
Furthermore, the Gila monster is protected by State law.