Poisonous Dwellers of the Desert :: Gila monster ( Heloderma suspectum )

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.

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.

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.

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.

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