Snaking around
the San Dieguito River Valley

by Park Ranger Ken Colburn           

  There are many different species of snakes that make their home in the San Dieguito River Valley, from racers to rattlesnakes.   In fact there are approximately 23 snake species that can be found in Southern California, see list.  I have personally seen 10 of these snake species within the San Dieguito River Valley.   The snakes more likely to be seen are the California Kingsnake, Two-Striped Garter Snake, Coachwhip, Gopher Snake, Southern Pacific Rattlesnake and the Red Diamond Rattlesnake.  

Snakes common to Southern California

1.   Western Blind Snake, Leptotyphlops humilis

2.   Rosy Boa, Charina trivirgata *

3.   Rubber Boa, Charina bottae

4.   Ring-Necked snake, Diadophis punctatus

5.   Chaparral Whipsnake or Striped Racer, Masticophis lateralis

6.   Western Yellow-bellied Racer, Coluber constrictor *

7.   Coachwhip, Masticophis flagellum *

8.   Baja California Racer, Masticophis flagellum fuliginosis

9.   Coast Patch-Nosed snake, Salvadora hexalepis *

10. San Diego Gopher Snake, Pituophis catenifer annectens *

11. California Glossy Snake, Arizona elegans

12. San Diego Mountain Kingsnake, Lampropeltis zonata

13. Common Kingsnake, California Kingsnake, Lampropeltis getula *

14. Long-Nosed Snake, Rhinocheilus lecontei *

15. California Red-Sided Garter Snake, Thamnophis sirtalis

16. Mountain Garter Snake, Thamnophis elegans

17. Two-striped Garter Snake, Thamnophis atratus *

18. California Black-Headed Snake, Tantilla planiceps

19. Night Snake, Hypsiglena torquata

20. Western Lyre Snake, Trimorphodon biscutatus

21. Southern Pacific Rattlesnake, Crotalus viridis *

22. Red Diamond Rattlesnake, Crotalus ruber *

23. Speckled Rattlesnake, Crotalus mitchellii

            Snakes are grouped into families based on specific physiological and morphological characteristics.   The six different families are Boidae, Colubridae, Elapidae, Viperidae, Leptotyphlopidae, and Hydrophiidae. Of these families only Boidae, Colubridae and Viperidae contain species that occur in our area.  

            Family Boidae; consists of the world’s largest snakes, boas and pythons, and has about 70 members.   Two species of boas occur in Southern California, the Rosy and Rubber boas.   They are both thick bodied snakes, usually no longer than 3 feet.   They have small heads, small eyes, blunt tails and have small, smooth scales.   They are good climbers and inhabit rocky areas with shrubs.   Though mostly nocturnal they can be found early in morning as well.   Primary diet consists of small mammals, lizards, frogs and birds.  

Here’s a picture of a Rosy Boa

            Family Colubridae; contains about 700 snake species world-wide, dispersed on every continent, except Antarctica. This family has the largest amount of diversity in habitats as well; terrestrial, burrowing, arboreal and aquatic species.  Within this family there are the Ring-Necked Snake, Western Yellow-Bellied Racer, Coachwhip, Chaparral Whipsnake, Coast Patch-Nosed Snake, Gopher Snake, California Glossy Snake, California Kingsnake, San Diego Mountain Kingsnake, Long-Nosed Snake, Two-Striped Garter Snake, California Black-Headed Snake, Western Lyre Snake and Night Snake in our area.   Due to the variability between the species it is hard to classify them by specific characteristics like other families, though their primary diet consists of small mammals, lizards and frogs.    

Here’s a picture of a Coachwhip, also known as the Red Racer.

California Kingsnake.

Two-Striped Garter Snake.

Here’s a picture of a Chaparral Whipsnake also known as a Striped Racer.

           San Diego Gopher Snake.

            Family Viperidae; contains about 157 species including the rattlesnakes, in our area the Southern Pacific and the Red Diamond Rattlesnake.   These snakes all have large, hollow, movable fangs at the front of the upper jaw, with the most developed venom delivery system, where the victim is stabbed and poisoned simultaneously in a rapid motion.    The venom of each snake is different and complex; there is no “standard” rattlesnake venom. Rattlesnake venom consist of combinations of proteins; hemotoxins, which break down cells and tissues, anticoagulants; which prevent wounds from closing and neurotoxins which cause circulatory and respiratory paralysis.   The rattlesnakes are also called pit vipers due to a small heat-sensing pit on each side of the face between the eye and nostril, which helps to locate their prey.   With this pit a snake can detect the heat from a candle flame 30 feet (9 m) away.   When disturbed, rattlesnakes will shake their rattles, so they are usually heard before they are seen.   Most are not very aggressive and will scurry off if left alone.   Their primary food consists of small mammals, birds, lizards and frogs.   

Rattlesnake Bites and Treatment

            Contrary to popular belief rattlesnakes do not always rattle before striking, neither must the snake be coiled before striking. If the snake feels threatened it may coil up, strike, retreat or not do anything at all.   Despite the toxicity of snake venom, less than 1 percent of the people bitten in the United States by venomous snakes die. If a rattlesnake bite occurs the best thing to do is remain calm and get to a hospital as soon as possible.  Modern medical facilities use the same rattlesnake antivenin (anti-venom) for all rattlesnake bites, so do not attempt to capture the snake.    

Rattlesnake Tips

1. Always look where your feet or hands are going before placing them.
2. Always identify things before you pick them up, such as the kind of snake.
3. Always carry a stick or tool in order to lift up things, avoid using your hands.
4. Always look under or over things; rocks, logs, before walking around them.
5. Always carry a flashlight when you are out at night.Do not hike in open-toed shoes.
6. Never pick up or play with a dead rattlesnake. They can still bite due to jaw reflexes.

Here’s a picture of a Southern Pacific Rattlesnake, referred to as Western Rattlesnake.

Red Diamond Rattlesnake.

Sources

            Stebbins, Robert. C., “Western Reptiles and Amphibians, third edition.” Peterson Field Guides. Houghton Mifflin Company. New York, New York. 2003.

            Snake pictures were taken by Chris Brown and can be found at http://www.werc.usgs.gov/fieldguide/snak.htm

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