gila monster

Kingsnakes versus Rattlesnakes

Kingsnakes eat rattlesnakes, hence their name. Apparently kingsnakes are either immune to or tolerant of rattlesnake venom. Kingsnakes also eat other snakes, lizards, amphibians, birds and bird eggs, and rodents.

Rattlesnakes can identify kingsnakes by smell. Rattlesnakes usually retreat in presence of a kingsnake and hold their head and tail close to the ground while arching their back and attempt to hit the kingsnake. Watch a 3-minute Discovery Channel video of a common kingsnake attacking and eating a rattlesnake:

Kingsnakes are usually docile, but when disturbed, they may hiss, vibrate their tail, and strike. If seized by a predator such as a coyote, the kingsnake can expel a noxious musk.

Kingsnakes come in a great variety of patterns and colors. There is some controversy over names and how many varieties there are. This is made more confusing because some varieties can interbreed with other varieties. I use the Arizona-Sonora Desert Museum naming convention here. Most kingsnake adults are three to six feet long. Below are photos of the most common varieties in the southwest. All kingsnakes have smooth scales unlike the ridged scales of the gopher snake. All kingsnakes are powerful constrictors.

Desert Kingsnake

Kingsnake desert

This black and white (or cream) is the most common kingsnake in the Tucson area. It is native to Arizona, New Mexico, and Texas. It normally grows to four feet but some are over six feet long. This kingsnake normally mates from March through June and produces up to 12 eggs that incubate for 60 days. Hatchlings are 8- to 10 inches long.

Common Kingsnake

Kingsnake common

The common kingsnake used to be called the California kingsnake. It has alternating brown/black and white/cream to yellow colored bands. Adults range from 2.5 to 6 feet long. This snake occurs throughout most of Arizona, California, and Baja California. Normal mating time is May through August. The females produce as many as 24 eggs which hatch in 60 days. Hatchlings are 6- to 8 inches long and are more brightly colored than the parents.

Sonoran Kingsnake

Kingsnake Sonoran

The Sonoran kingsnake is usually deep chocolate brown which may look black in some lighting conditions. It occurs in southern Arizona and in Mexico south to Sinaloa. Young snakes may have spots of white or yellow under their chin. This snake is commonly 3- to 4 feet long and rather plump compared to other kingsnakes.

Mountain Kingsnake

Kingsnake Arizona Mtn

This pretty snake is variously called the Arizona Mountain kingsnake or Sonoran Mountain kingsnake, It may be 2.5 to 4 feet long. This snake inhabits the Sierra Madre in Sonora and several mountain ranges in southern Arizona. I have seen this snake in the Bradshaw Mountains near Jerome. Some occur also in Utah and Nevada. It may be confused with the coral snake, but it is much larger. Remember the rhyme: “Red touch black, OK Jack.” These snakes breed in spring and generally produce four to nine eggs.

Milk snake

Kingsnake Sinaloan Milksnake

On this snake, the red bands are much wider than the black and white/yellow bands. It, too, can be confused with the coral snake. The rest of the rhyme: “Red touch yellow, kill a fellow.” In kingsnakes, the red band is surrounded by black bands.

The milk snake is commonly 1.5- to 4.5 feet long. It occurs mainly in southern Sonora, but there have been some specimens collected near the Little Colorado River in northern Arizona. This snake occurs mainly in forests and is mainly nocturnal. Breeding is similar to the mountain kingsnake.

I handle snakes at the Arizona-Sonora Desert Museum including all the kingsnakes shown above. Kingsnakes are my favorite snake. They seem more curious than other snakes. When I’m holding a snake and someone comes near, the kingsnake will take a look and flick its tongue to get a taste. Taste, by the way, is the snake’s most important sense. Their forked tongue picks up particles in the air which are analyzed by the Jacobson’s organ in the roof of the mouth. The organ is so sensitive that it can distinguish differences from each side of the forked tongue. This gives the snake a sense of direction for where the taste is coming from.

Kingsnakes have many pointy teeth to grip their prey. In the photo below, notice that snakes have four rows of teeth on top. Notice also that the teeth are very small. I have never been bitten, but other Docents have been. They say it is no big deal because the teeth are so small.

 Snake teeth

Besides the western kingsnakes described above, several species, mainly black varieties, live in the mid-western and eastern states. The eastern kingsnakes eat copperheads as well as rattlesnakes.

Be kind to kingsnakes you find in your yard. They will help protect you from rattlesnakes and eat rodents.

See also:

Gopher snakes
Clever Horned Lizard
Metachromatic spiny lizards
Speckled Rattlesnakes
Venomous Lizards (Gila monster, Beaded lizard)

Old mines of the Tucson Mountains

Back in the late 19th Century and early 20th Century, much prospecting was done in the volcanic mountains west of Tucson.  Approximately 120 mines and prospects were explored for copper, gold, and silver.  According to the National Park Service, the first claim was registered in 1865.

The Tucson Mountains are composed of a volcanic edifice that collapsed into a caldera about 70 million years ago.  The caldera was about 12 miles by 15 miles wide.  The volcano collapsed as the result of eruption of volcanic ash which piled up in flows that reached an accumulated thickness of about three miles.  Toward the end of the volcanic episode, magma rose and penetrated the flows, metamorphosing some, and bring with it, hydrothermal solutions carrying copper, gold, silver, and other metals.  A more detailed overview of the process is presented in Sonorensis, a publication of the Arizona-Sonora Desert Museum here.  See also a history of the district prepared by the National Park Service here.

Most of those 120 odd prospects were just holes in the ground, but four mines had some consequence: Old Yuma, Gila Monster, Mile Wide, and Gould mines. (See map at the bottom of this post for locations.) Of the four, the Old Yuma mine was the most famous, not for its ore, but for its museum quality mineral specimens.

The Old Yuma Mine

According to Dr.  Jan C. Rasmussen, formerly with the Arizona Bureau of Mines and Mineral Resources:


The Old Yuma mine in the northern Tucson Mountains was primarily a gold mine, most recently owned by Richard Bideaux.  The mineralization consists of partly oxidized  base- metal sulfides with spotty wulfenite and vanadinite, and gangue quartz and calcite.  The minerals occurred as a steeply dipping, lensing and faulted orebody along a fracture zone cutting Cretaceous volcanics and associated with a  Laramide porphyry intrusive, the Amole Granite.  Shaft and underground workings produced ore from 1916-1947, totaling 5,700 tons ore grading 4% lead, 1% copper, 0.6% zinc, 0.3% molybdenum, 1 ounce silver per ton, and 0.1 ounces gold per ton.  The mine is now in a national park and unavailable for collecting.


In the latter part of the 20th Century, this mine was prized for its mineral specimens.  The two photos are of specimens in the Arizona-Sonora Desert Museum collection (Photo credits to ASDM digital library).  The first photo is wulfenite (PbMoO4), an mineral sometimes used as a source of molybdenum.  The second photo is vanadinite (Pb5(VO4)3Cl) one of the main sources of vanadium.


Gila Monster Mine

The Gila Monster mine was located about one and a half miles south of the Old Yuma.  It was developed on a vein of lead, zinc, copper mineralization adjacent to a large block of limestone that was engulf in the caldera volcanics.  Production was minor, but interesting specimens of red-fluorescing calcite  and willemite, a zinc silicate (Zn2SiO4) were taken from the mine.

Mile Wide Mine

The Mile Wide mine, located about a mile and a half north of the Desert Museum, mined stockholders.  According to a history by the National Park Service, the mine was optioned in 1915 to Charles Reiniger :

Reiniger established the Mile Wide Copper Company. It was so named because the width of the claims was a mile wide. He concentrated on the Copper King which became known as the Mile Wide Mine. In the process of development Reiniger abandoned the old shaft in favor of a new site up the hill. While mining at that location he reported a copper strike which purportedly would be the equal if not superior to the largest Arizona copper mines. As a result, stock sales increased and Reiniger further developed the property. He built four houses, a work shop, mess house, rock crusher, and mill. In addition he improved the road to make it possible for his six trucks to haul more ore to Tucson for rail shipment to the smelter at Sasco which was just north of Silver Bell.

Reiniger used the mining activity and the promotional hype to practice fraud on the stockholders. In late 1919 he disappeared taking half the money derived from stock sales. In addition he sold up to $100,000 of his own stock before his departure.

The Gould Mine

The Gould mine was located half a mile south of the Mile Wide mine.  It was established in 1906 and produced 45,000 pounds of copper before it ceased operations in 1911.

It seems that the mines of the Tucson mountains were teasers, lots of smoke, little fire.


Venomous Lizards

The are only two venomous lizard species in the world and both live in this general region. The Gila Monster and the Mexican Beaded Lizard.

Gila Monster



The Gila monster (Heloderma suspectrum) averages 9- to 14 inches long, but can get up to 24 inches long. It ranges throughout the Sonoran Desert region below about 4,000 feet elevation. Its range included parts of Arizona, California, Nevada, New Mexico and northern Sinaloa, Mexico. It feeds on eggs of reptiles and birds, and takes small rodents, such as pack rats, and baby mammals such as rabbits and squirrels. Mating occurs in spring or early summer. Observations in the wild suggest an incubation period of 10 months, but captive lizards produce hatchlings in about 4 months. There are two subspecies of Gila monster: the reticulate Gila monster (H. suspectum suspectum) and the banded Gila monster (H. suspectum cinctum). The reticulate Gila monster lives in the southern region part of the range, while the banded Gila monster occurs primarily in the Mojave Desert. The reticulate Gila monster tends to have its lighter markings broken up by dark scales, giving it a reticulated pattern, while the banded Gila monster generally has more unbroken bands of lighter scales.

The Mexican beaded lizard (Heloderma horridum) averages 2- to 3 feet long. It ranges throughout southern Sonora. It feeds on birds, small mammals, other lizards, and eggs. It can climb trees. Little is know about mating in the wild. Captive lizards mate in August, produce eggs in October which hatch from January to March.

Both lizards have forked tongues which they use to sample the air to find prey. They are nocturnal hunters. The thick tails store fat. Both lizards are dormant during the winter, and both spend about 95% of their time underground. A young gila monster can eat the equivalent of 75% of its body weight at one meal; an adult can consume 50% of its body weight at one meal.

The venom is a neurotoxin similar to that of a coral snake. It is released from glands in the lower jaw and conducted through grooved teeth by capillary action and chewing. The lizards don’t have fangs; they just chew on you for a while, without letting go. The lizards are very tenacious. Study of the venom suggests it evolved as a defensive toxin. Bites to humans are rare. Victims have reported intense pain within five minutes of the bite and the pain may persist for several hours. Weakness, dizziness, perspiration, nausea, chills, and fever have been reported. No human deaths have been reported.

Research shows more than a dozen peptides and proteins have been isolated from the Gila monster’s venom, including hyaluronidase, serotonin, phospholipase A2, and several kallikrein-like glycoproteins responsible for the pain and edema caused by a bite. Four potentially lethal toxins have been isolated from the Gila monster’s venom, including horridum venom, which causes hemorrhage in internal organs and bulging of the eyes, and helothermine, which causes lethargy, partial paralysis of the limbs, and hypothermia in rats. However, the constituents most focused on are the bioactive peptides, including helodermin, helospectin, exendin-3, and exendin-4. Most are similar in form to vasoactive intestinal peptide (VIP), which relaxes smooth muscle and regulates water and electrolyte secretion between the small and large intestines. These bioactive peptides are able to bind to VIP receptors in many different human tissues. One of these, helodermin, has been shown to inhibit the growth of lung cancer.

Although Gila Monsters have a fearsome reputation, they are sluggish and pose little threat to humans, just don’t try to pet one or pick one up.

Myths about Gila monsters include: how the Gila monster is venomous because it lacks an anus and “all that stuff went bad in there.” Or about how “once they bite down, they can’t let go until sundown,” or “if one bites you, don’t worry, it has to turn upside down to get the venom in you.” (ASDM).

In 1952 the Gila monster became the first venomous animal in North America to be afforded legal protection; it is therefore illegal to collect, kill, or sell them in Arizona.