Pituophis catenifer

The species' range extends from southern British Columbia to Indiana, and south through all of western North America to northern Baja California (Grismer 2002), Sonora, Sinaloa and Zacatecas in Mexico.

Pituophis catenifer is found from southwestern Canada south to northern New Mexico. Gopher snakes are found from south-central British Columbia and southern Alberta and Saskatchewan, through the central and western United States, and south through Baja California and Sinaloa, Durango, Zacatecas, and Tamaulipas states in Mexico. In the United States they are found from the Pacific coast eastwards to Wisconsin, Illinois, Missouri, Oklahoma, and western Texas. There are 11 subspecies recognized, with some of those proposed as valid species, including P. c. vertebralis, from southernmost Baja California. Several subspecies represent isolated, island forms, including Cedros Island gopher snakes (P. c. insulanus), San Martin Island gopher snakes (P. c. fuliginatus), Coronado Island gopher snakes (P. c. coronalis), and Santa Cruz gopher snakes (P. c. pumilis).

Biogeographic Regions: nearctic (Native )

Other Geographic Terms: island endemic

endemic to a single nation

Canada

Origin: Native

Regularity: Regularly occurring

Currently: Present

Confidence: Confident

Type of Residency: Year-round

United States

Origin: Native

Regularity: Regularly occurring

Currently: Present

Confidence: Confident

Type of Residency: Year-round

Global Range: (>2,500,000 square km (greater than 1,000,000 square miles)) The range extends from southern British Columbia, southern Alberta, southern Saskatchewan, Minnesota, and Indiana south through almost all of western and central North America to northern Baja California (Grismer 2002) (or to southern Baja California if P. vertebralis is included in P. catenifer; Rodriguez-Robles and De Jesus-Escobar 2000), Sinaloa, and Zacatecas.

Continent: Middle-America North-America
Distribution: Canada (British Columbia, Alberta, Saskatchewan), USA (Washington, Oregon, Wisconsin, Illinois, Indiana, Kansas, South Dakota, California, New Mexico, Arizona), Mexico  affinis: W Texas to SE California and south to Mexico (Zacatecas and S Sinaloa, San Luis Potosi).  sayi: Colorado, Kansas, Minnesota, Nebraska, Oklahoma (BURT 1935), Wisconsin

Gopher snakes range in body length from 180 to 275 cm. They have relatively large heads, narrow necks, and large eyes as compared to most species of similar body length. Gopher snakes are marked with brown to black blotches on a background color of lighter straw to gray. Color patterns vary regionally and often mimic the colors of the dominant cover vegetation in a region. Individuals that are blotched, striped, or even albino are known from wild populations. Their ventral surface is generally white to yellowish, sometimes with dark spots. They usually have a dark line across the face in front of the eyes and from behind the eyes to the angle of the jaw. Gopher snakes have keeled scales and a single anal scale. They have 27 to 37 scale rows at their midbody. Superficially, gopher snakes resemble many species of rattlesnakes and are often mistaken for them. Gopher snakes are not venomous and do not have rattles on the end of their tail.

Range length: 180 to 275 cm.

Other Physical Features: ectothermic ; heterothermic ; bilateral symmetry

Sexual Dimorphism: sexes alike

Length: 168 cm

Differs from other similar species by having the following combination of characteristics: keeled scales, 4 prefrontals, and an undivided anal. Rat snakes (ELAPHE) and kingsnakes (LAMPROPELTIS), have only two prefrontal scales. Also, ELAPHE has a divided anal plate. Whipsnakes (MASTICOPHIS), racers (COLUBER), and indigo snakes (DRYMARCHON) have smooth body scales.

Habitat and Ecology

Systems

• Terrestrial

Gopher snakes are found in a wide variety of habitats, including woodlands, deserts ,agricultural areas (such as cultivated fields), prairies, chaparral, and shrublands. Radiotelemetry studies have shown that, although they are often found near moist habitats, such as marshes and moist woodlands, they prefer to spend most of their time in open parts of those habitats, such as grassland and forest edges. This preference is likely related to foraging activities.

Habitat Regions: temperate ; terrestrial

Terrestrial Biomes: desert or dune ; savanna or grassland ; chaparral ; forest ; mountains

Other Habitat Features: suburban ; agricultural ; riparian

Comments: This species occurs in a wide range of habitats, extending from lowlands to mountains: desert, prairie, shrubland, woodland, open coniferous forest, farmland, and marshes. Midwestern populations inhabit prairies; western and Mexican populations range from coastal grasslands and forests through deserts into montane forests (Sweet and Parker 1990). This snake is terrestrial, fossorial, and arboreal. It remains underground in cold weather and during the hot midday period in summer; it may occupy mammal burrows (Schroder 1950, Fitch 1958) or dig its own burrow, aided by the pointed snout and enlarged rostral scale. Carpenter (1982) estimated that burrowing Pituophis could move up to 3,400 cubic cm of soil in an hour. Eggs are deposited in burrows excavated by females in loose soil, in spaces beneath large rocks or logs, or possibly in small mammal burrows.

Non-Migrant: Yes. At least some populations of this species do not make significant seasonal migrations. Juvenile dispersal is not considered a migration.

Locally Migrant: Yes. At least some populations of this species make local extended movements (generally less than 200 km) at particular times of the year (e.g., to breeding or wintering grounds, to hibernation sites).

Locally Migrant: No. No populations of this species make annual migrations of over 200 km.

In Utah, migrated an average of about 500 m between winter den and summer range (Parker and Brown 1980).

Imler (1945) recaptured 11 snakes that had moved less than 100 m, but reported one snake moving 2.4 km. In Kansas, Fitch (1958) reported movements between captures of 94, 128, and 823 m. Radio-telemetered snakes in Kansas moved an average of 142 m in a day (Fitch and Shirer 1971). Home range was estimated at 1-2 ha in Utah (Parker and Brown 1980).

In west-central California, four males had home ranges of 1.0-2.3 ha (mean 1.7 ha) (95% convex polygon); maximum range length was a few hundred meters (Rodriguez-Robles 2003).

Gopher snakes use constriction to capture and kill their prey. Typical prey include small mammals, birds, lizards, smaller snakes, insects, and eggs. Prey varies regionally but the primary prey in all areas are rodents and other small mammals. In some areas they prey mainly on gophers (Geomyidae), which is why they are called "gopher snakes." Gopher snakes actively search for prey in their burrows and hiding places. They often follow small mammal runways, and are quite successful in capturing voles (Microtus), western harvest mice (Reithrodontomys megalotis), Peromyscus species, kangaroo rats (Dipodomys), ground squirrels (Spermophilus), and young rabbits (Sylvilagus). They have also been known to eat bats in roosts. Lizards and snakes taken include side-blotched lizards (Uta) and rattlesnakes (Crotalus). They take birds, eggs, and insects occasionally as well.

Animal Foods: birds; mammals; amphibians; reptiles; eggs; insects

Primary Diet: carnivore (Eats terrestrial vertebrates)

Comments: Feeds primarily on small mammals; also eats birds and their eggs, lizards, small snakes and snake eggs, and insects; lizards and insects are more common in the diet of juveniles than in that of adults. Forages actively and locates prey either by olfaction or sight (Dyrkacz and Corn 1974, Chiszar et al. 1980). Often forages underground, but in some areas also commonly climbs trees to prey on nesting birds (e.g., Eichhorn and Koenig 1992).

See Diller and Johnson (1988) for predation rate on small mammals in southwestern Idaho.

Gopher snakes play an important role in the ecosystems in which they live. They are important predators of small mammals, many of which are considered pests by humans. Gopher snakes can greatly reduce the numbers of small mammals in an area.

Parasite surveys have discovered mites (Trombicula arenicola) on gopher snakes, as well as ticks, fleas, and chiggers. Internal parasites include a blood protozoan (Hepatozoon serpentium) and an intestinal parasite (Tritrichomonas batrachorum).

Commensal/Parasitic Species:

• mites (Trombicula arenicola)
• blood protozoan (Hepatozoon serpentium)
• intestinal parasite (Tritrichomonas batrachorum)

Kit foxes Vulpes macrotis , red-tailed hawks Buteo jamaicensis, and coyotes Canis latrans are the most common predators of the gopher snake. They are probably also preyed on by other foxes (Vulpes vulpes and Urocyon cinereoargenteus), hawks (Accipitridae), and large king snakes (Lampropeltis). Gopher snakes are cryptically colored and remain hidden except when actively pursuing prey or basking in open areas. They are large snakes and can inflict a painful bite if harassed. They also behaviorally mimic rattlesnakes by coiling, raising their heads, and rapidly shaking their tails when threatened by a predator or unsuspecting human. Their rattlesnake mimicry can be very convincing and many gopher snakes are killed as rattlesnakes. Non-human predators are likely to be discouraged from attacking gopher snakes when they are mimicing rattlesnakes.

Known Predators:

• red-tailed hawks (Buteo jamaicensis)
• kit foxes (Vulpes macrotis)
• coyotes (Canis latrans)

Anti-predator Adaptations: mimic; cryptic

Pituophis catenifer preys on:
Sitta pygmaea

This list may not be complete but is based on published studies.

Note: For many non-migratory species, occurrences are roughly equivalent to populations.

Estimated Number of Occurrences: > 300

Comments: This species is represented by hundreds of occurrences or subpopulations (see map in Sweet and Parker 1990).

>1,000,000 individuals

Comments: Total adult population size is unknown but certainly exceeds 100,000 and probably exceeds 1,000,000. This snake is relatively common in many areas.

Population density was estimated at 0.3-1.3/ha in Utah and Idaho (Parker and Brown 1980, Nussbaum 1983).

This snake is remarkably variable in its behavior. Some individuals lie motionless when approached, remaining passive even when handled. Others respond to approach by coiling and striking (often lunging forward and grunting with each strike), hissing loudly, and vibrating the tail. The jaws may be spread, giving the head the triangular shape typical of rattlesnakes. In dry vegetation the vibrating tail may produce a sound resembling that made by a rattlesnakes rattle. Some individuals produce a rattling hiss that closely resembles the sound of a rattlesnakes rattle. Source: Hammerson (1999).

Because they are primarily solitary, there is little communication among Pituophis catenifer individuals. During mating season, females indicate they are ready to mate by releasing skin secretions. Gopher snakes use their tongues and vomeronasal organs to "smell" their surroundings. They also use vision, touch, and sensing vibrations to perceive their environment.

Communication Channels: chemical

Other Communication Modes: pheromones

Perception Channels: visual ; tactile ; vibrations ; chemical

Comments: Activity occurs from about April through October in the north, mostly March through November farther south(Nussbaum et al. 1983, Tennant 1984). In southwestern Idaho, seasonal activity peaked in late May and early June (Diller and Wallace 1996). Generally this snake is diurnal, but it may be active at night, largely fossorial, or exhibit bimodal morning and evening activity in hot weather.

Gopher snakes are oviparous and have an incubation period of about 65 to 75 days. When hatched the young measure 30 to 35 cm in length. After hatching, Pituophis catenifer exhibits indeterminate growth. In the first three years growth is rapid, then slows for the rest of their life.

Development - Life Cycle: indeterminate growth

The average life span in wild gopher snakes is 12 to 15 years. In captivity they have been known to live for as long as 33 years.

Range lifespan
Status: captivity: 33 (high) years.

Typical lifespan
Status: wild: 12 to 15 years.

Maximum longevity: 33.8 years (captivity)

Males compete for access to reproductively receptive females. Receptive females emit skin secretions that males detect through chemosensation and stimulates mating behaviors. Males will attempt to mate with as many receptive females as they can find. Males and females don't generally associate before or after mating.

Mating System: polygynandrous (promiscuous)

Gopher snakes breed once yearly, usually in June to August. Some females lay two clutches each year. They are oviparous and have an incubation period of 65 to 75 days. Once the 2 to 24 young hatch from the eggs, they are left to fend for themselves. It takes about 4 years for females to reach sexual maturity, but only 1.5 years for males.

Breeding interval: Gopher snakes usually breed once a year, although some females may have 2 clutches.

Breeding season: Breeding usually occurs from June to August.

Range number of offspring: 2 to 24.

Range gestation period: 65 to 75 days.

Range age at sexual or reproductive maturity (female): 3 to 5 years.

Range age at sexual or reproductive maturity (male): 1 to 2 years.

Key Reproductive Features: iteroparous ; seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; fertilization ; oviparous

Females lay their eggs in nests, which are sometimes communal. After the eggs are laid there is no further parental care.

Parental Investment: no parental involvement; pre-fertilization (Provisioning, Protecting: Female); pre-hatching/birth (Provisioning: Female, Protecting: Female)

The mating period extends from April to early June over much of the range (Ernst and Barbour 1989). Eggs are laid as early as June in some areas or as late as August in other regions (Ernst and Barbour 1989). Clutch size is 2-24. Generally individual females produce one clutch per year. Incubation typically takes 50-100 days, with 70-75 days most common (Parker and Brown 1980, Ernst and Barbour 1989). In many areas, hatchlings emerge in August and September. In Utah, males reach sexually maturity in 1-2 years, females in 3-5 years (Parker and Brown 1980). Females appear to have an annual breeding cycle (Fitch 1970, Diller and Wallace 1996).

Barcode of Life Data Systems (BOLDS) Stats
Public Records: 0
Specimens with Barcodes: 3
Species With Barcodes: 1

Canada

Rounded National Status Rank: N4 - Apparently Secure

United States

Rounded National Status Rank: N5 - Secure

Year Assessed

Assessor/s

Reviewer/s

Justification

Pituophis catenifer is fairly stable throughout its range and is listed as a species of "Least Concern" on the IUCN list. Island populations may be especially susceptible to environmental changes or persecution.

US Federal List: no special status

CITES: no special status

State of Michigan List: no special status

IUCN Red List of Threatened Species: least concern

Rounded Global Status Rank: G5 - Secure

Reasons: Large range from southern Canada to Mexico; common in many areas.

Intrinsic Vulnerability: Moderately vulnerable

Population

Population Trend

Global Short Term Trend: Relatively stable (=10% change)

Comments: Extent of occurrence, area of occupancy, number of subpopulations, and population size probably are relatively stable or declining at a rate of less than 10 percent over 10 years or three generations.

Global Long Term Trend: Increase of 10-25% to decline of 30%

Degree of Threat: Medium

Comments: No major threats exist. Local declines have occurred in areas with extensive, intensive agricultural or urban development, but these snakes persist in semiagricultural landscapes and rural residential areas.

Major Threats

Conservation Actions

Global Protection: Very many (>40) occurrences appropriately protected and managed

Comments: Many occurrences are in protected areas.

When harassed, gopher snakes can inflict a painful bite, depending on their size. But these snakes are non-venomous and will only bite in self-defense. Gopher snakes are sometimes mistaken for rattlesnakes because of their size, coloration, and habit of wiggling their tail when they feel threatened.

Negative Impacts: injures humans (bites or stings)

Gopher snakes are important predators on crop pests and play a role in agricultural losses to rodents. They are also good pets if well cared for. Gopher snakes are sometimes killed because they are mistaken for rattlesnakes, which they superficially resemble, but gopher snakes are harmless and beneficial snakes.

Positive Impacts: pet trade ; controls pest population