The Crestone Eagle, April 2006:

Serpentine wild neighbors (Part 3 of 3)
by Keno

In part 3 of our look at small wildlife in the Crestone area we will examine snakes. We do not have many snakes in the Crestone area, the main reason being that our elevation averages 8,000’, with most snakes preferring to live below 6,000’. There are many rattlers on the west side of the Valley and further south along the Sangres.

Most Colorado snakes are nonvenomous (i.e. nonpoisonous), harmless and beneficial to people. It should also be noted that nonvenomous and venomous species can be easily distinguished from each other.

Humans have coped with snakes for centuries, yet the ancestors of snakes appeared long before our own predecessors. Their roots date back to the Triassic period, approximately 190 million years ago. Snakes possess the following reptilian characteristics: they have scales, are ectothermic (they rely on external sources to control their body temperature), and, like most reptiles, most of them lay eggs.

Most snakes prey predominantly on rodents, ground squirrels or rabbits, although some also eat bird eggs, nestlings, lizards, and insects. They, in turn, are prey for eagles, hawks, foxes, coyotes, skunks, raccoons, badgers and humans. Domestic cats will go after them, too. Pigs, chickens, sheep and horses have been known to kill snakes, especially in areas with venomous snakes, but this is more a result of instinctive fear rather than true predation.

Colorado has 25 species of snakes, the western rattlesnake (aka prairie rattlesnake—Crotalus viridis) and the Massasauga rattlesnake—(Sistrurus catenatus) are the only venomous species in the state (in the United States there are only a total of four venomous snakes—coralsnake, copperhead, cottonmouth water moccasin and rattlesnake).

The western rattlesnake appears in most habitats throughout Colorado. The Massasauga however, is limited to the southeastern grasslands and is not found in our area. There are six basic ways to distinguish these two venomous snakes from their nonvenomous relatives: 1) rattles at the end of the tail; 2) fangs in addition to their rows of teeth; 3) facial pits between the nostrils and eyes; 4) vertical and elliptical pupils that may look like thin lines in bright light (nonvenomous snakes have round pupils); 5) a single row of scales between the vent and the tip of the tail. (nonvenomous snakes have two rows of scales); 6) broad triangular head and narrow neck.

There are only two kinds of snakes in the Crestone area, bull snakes and garter snakes. Rattlesnakes live in our county, along with 14 other kinds of snakes in neighboring counties. We will only look at the three that call Saguache County their home.

Rattlesnakes
Perhaps the main reason there have never been any rattlesnakes reported in Crestone is because they prefer to live below 7500’ feet. They are nearby, for the most part, west of Highway 17 and south of the Great Sand Dunes.

Rattlesnakes are poisonous snakes and all rattlesnakes possess a rattle at the end of their tail. Like all snakes, rattlers are cold-blooded, which means they are the same temperature as the environment. The length of an adult western rattlesnake averages 4 1/2 feet, maximum length 6 1/2 feet. They continue to grow all their lives, getting bigger each year. They are usually a lighter gray or brown color with darker, rounded or diamond shaped patterns that are edged in a contrasting color. They also have a light stripe from their eye to the corners of their mouths. They have two rows of similar, but smaller blotches on their sides, with a wide head, narrow neck, and stout body.

Rattlesnakes are carnivores (meat-eaters). They mostly hunt at night. They are nocturnal and can sense the heat of their potential prey. Rattlers kill prey with venom, which also contains digestive enzymes that begin to dissolve the meat even before the snake eats it. Like all snakes, they swallow prey whole, head first.

In all of Colorado, rattlesnakes spend the winter hibernating in a lair with many other rattlers. These spots are known as snake dens. Mating occurs in the spring. Most snakes lay eggs, but with rattlesnakes eggs are retained in the mother’s body until hatched, with the young being born live. The female rattler may contain from 4 to 25 eggs, from which an average of 9 or 10 hardy young are born live. They will give birth in the autumn, with each baby being 10 inches or more in length.

Young rattlers are completely independent of the mother. They only remain in the area of their birth for the first 7 to 10 days, until they shed their baby skin and add their first rattle. The litter will then disperse and begin the search for food. Many newborns do not survive the first year, either dying of hunger or being eaten by birds and other animals. Many will perish during the first winter, if they can’t find a suitable warm den in which to hibernate.

According to the Colorado Division of Wildlife, it is legal to kill rattlesnakes only when necessary to protect life or property. The most common method to kill a rattlesnake is clubbing or shooting. The western rattlesnake and all nonpoisonous snakes are classified as non game wildlife and are protected by state law, except as noted above.

Rattlers try to avoid humans. If bitten by a rattlesnake, remain as calm as possible. They do not always release venom when they bite. If venom is present, panic will only increase your heart rate, which will cause the poison to circulate more quickly throughout your body. Do not try to kill the snake because it may lead to additional bites and delay your arrival at the hospital for treatment. There is antivenin available for use against all native pit vipers in the United States, so it is no longer imperative to determine the species of rattlesnake. The most useful snakebite first aid kit is car keys and a phone for calling the hospital. If possible, have another person drive and call ahead to the hospital to let them know you are on the way. One final note, all of the other treatments for treating snake bites (like suckling out the poison with your mouth)—forget about them—get to the hospital, the sooner the better!

Bull snakes
There is a very slight difference between bull snakes (Pituophis catenifer sayi) and gopher snakes (Pituophis catenifer deserticola), and what we have living in Crestone are called bull snakes, which are closely related to pine snakes (Pituophis melanoleucuss). The bull snake is a hissing constrictor—a snake that kills by squeezing prey until the victim can no longer breathe.

Members of the Colubridae family, the large bull snake is usually between 36” and 80” long, with some as long as 110”. They range in color from green-gray to tan to cream-yellow, with large black, brown or reddish blotches on their back and smaller ones along their sides. Most have a dark line between the eyes and another from behind the eyes to the angle of the jaw. Sometimes striped individuals, with or without blotches, are found. They have a moderately stout body, with keeled scales.

This snake is most active during the day. They eat every 10 days. Bull snakes are good tree climbers, and they will search for prey in burrows, dens and rocks. When alarmed, they coil into an S-shape, hiss loudly and rapidly vibrate their tails on the ground, mimicking the warning of the similar-looking rattlesnake. Because of this action, people sometimes mistake them for rattlesnakes. In the winter, bull snakes hibernate, retreating to communal dens, sometimes sharing the lair with rattlesnakes.

In the breeding season, males vigorously defend their territories against all competing males. Six weeks after mating, the female will lay a clutch of eggs with 2—24 eggs each. The eggs incubate for about 70 days depending on temperatures, and hatchlings emerge fully developed within 10 weeks and are 12-18 inches in length, large enough to eat small mice. Bull snakes in the wild reach maturity in 3-4 years. Their total life span is around 12 years in the wild, but in captivity they can live 20+ years.

Their range in our state is usually below 8500’, so you’re more likely to see them out in the Grants than in our mountains.

Garter snakes
Often miscalled garden or gardener snakes, garter snakes (aka water snake—Thamnophis spp—meaning bush snake) are found all over Colorado, including here in Crestone, where the western terrestrial garter snake (Thamnophis elegans) lives. Garter snakes are one of the most common of snakes, having the northernmost range of all North American snakes, they can be found from the Yukon down to Costa Rica, and from the Pacific to the Atlantic coasts. They are the most likely snake to be found in Crestone.

Garter snakes rarely exceed three feet in length and remain a slender two inches in girth. There are fifteen species in the United States, with ten species (plus subspecies) occurring in the western U.S. In Colorado, they are found up to 11,000’, but have been found at over 13,000’ in some areas. Depending upon their species, they live from 3-10 years. Due to their small size, garters heat up and cool down quickly. Like most reptiles, they warm up by basking in the sun. They strive to maintain their body temperature between 72° and 88° F.

The garters here in Crestone are generally brown to gray or gray and light tan checkerboard pattern in juveniles, which darkens and becomes obscure with age. A light stripe down sides of body also becomes less prominent with age. They are quite agile, a trait which also enables them to successfully capture prey. They encounter their prey while moving through their territory during the cooler parts of the day—early morning, late afternoon and early evening. Garter diets range from birds to mammals. Large prey may be pushed against a rock to anchor it in place while the snake works its jaws around it. They rarely constrict their prey, instead stunning or killing it before eating.

Garters living in Crestone must hibernate during the winter due to the cold and reduced number of hours available for sunlight basking. They will stock up on body fat by feeding heavily during the late summer. They hibernate in aggregations—hundreds of snakes might gather in the same location, spending the winter together and then being accessible to each other for spring breeding. Males, upon emerging from hibernation, become sexually active, ensuring that females will be mated at the time they leave the den. Their young are born in the late summer. The litter size is from 10-30, with some litters recorded as much as 60-85 offspring. The young’s average size is 9”. They are independent from birth.

Predators of garters are normally smaller animals, with the larger carnivores only occasionally catching and eating them—as they normally don’t bother much with them because of their small size, which doesn’t make it worth the expenditure of time and energy necessary to capture them.

A final note on all snakes. They can and do get into our homes. They come in the same way mice do —through holes in the foundation. This can be solved by caulking and sealing all holes. Also, reduce cover and food supplies to discourage them from living anywhere on your property.

If they do get in, there are two best ways to get rid of them by either placing a box over the snake and sliding a piece of cardboard underneath the box or by sweeping the snake into a large bucket with a broom to release outdoors. You can also just pick them up gently behind the head, as long as they are nonpoisonous, which should always be the case in Crestone.

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