Docstoc

Clark, H.O., Jr. 2012. Rattlesnake mimicry in the Pacific Gopher Snake (Pituophis catenifer catenifer). Sonoran Herpetologist 25(8):78

Document Sample
Clark, H.O., Jr. 2012. Rattlesnake mimicry in the Pacific Gopher Snake (Pituophis catenifer catenifer). Sonoran Herpetologist 25(8):78 Powered By Docstoc
					N AT U R A L H I S TO RY N OT E

Rattlesnake Mimicry in the Pacific Gopher Snake (Pituophis catenifer catenifer)
Howard O. Clark, Jr., Senior Widlife Ecologist, H. T. Harvey & Associates, Fresno, California 93711; hclark@harveyecology.com


Mimicry of israttlesnakes by
gopher snakes well known
(Bezy 1993, Sweet 1985), how-
ever there are times where the
mimicry is so well done that a
double-take is necessary to tell
the two species apart.
    On the evening of 25 May
2012, I was driving home
from work on a highway that
bisects habitat occupied by
both the Pacific Gopher Snake
(Pituophis catenifer catenifer) and
the Western Rattlesnake (Cro-
talus oreganus). Oftentimes I see
both species stretched out on
the pavement in the evenings
absorbing the released heat.
I pull over to examine these                                                                                                                    Mimicry of
snakes and remove them from
the road to prevent vehicle strikes. At approximately                          Figure 1. Pacific Gopher Snake (Pituophis catenifer catenifer)   rattlesnakes by
                                                                                          mimicking a rattlesnake. Photo by Howard Clark.
1845 I observed a snake on State Route 33 in Kings                                                                                              gopher snakes
County, CA (at mile marker 4.0), that at first glance ap-                species commonly confused for one another. Although
peared to be a gopher snake. I turned around to exam-                    the details remain unclear, confusion of a krait with its              is well known
ine it closer. Using a wooden stick, I moved the snake                   mimic may have been the cause of the bite that led to                  (Bezy 1993,
off the highway onto the shoulder (Figure 1). I was                      the death of a noted herpetologist (James 2008).
a bit surprised to see something that looked remark-                                                                                            Sweet 1985),
ably like a rattlesnake. It had a triangle-shaped head                   Literature Cited                                                       however there
and was striking at me like a viper would from a coiled
position. I took some photos and continued home.
                                                                         Bezy, R.L. 1993. Southland Diorama: The Gopher                         are times where
                                                                            Snake. Terra 31:40-41.
Once I downloaded the photos I decided to send my
                                                                         James, J. 2008. The Snake Charmer: A Life and Death                    the mimicry is so
best photo to the editor of Herpetological Review, Robert
Hansen. He said it was definitely a gopher snake and
                                                                            in the Persuit of Knowledge. Hyperion. 272 pages.                   well done that
                                                                         Sweet, S.S. 1985. Geographic Variation, Convergent
my photo illustrated very well what they do best:
                                                                            Crypsis and Mimicry in Gopher Snakes (Pituophis                     a double-take is
behavioral mimicry of vipers. I was impressed with
this particular snake in its ability to shape its head to
                                                                            melanoleucus) and Western Rattlesnakes (Crotalus                    necessary to tell
                                                                            viridis). Journal of Herpetology 19:55-67.
resemble a rattlesnake. I’ve seen gopher snakes mimic                                                                                           the two species
rattlersnakes before but the head always
appeared narrow. This particular snake                                                                                                          apart.
did not rattle its tail but did vigorously
strike at me from a coiled position.
    Rattlesnakes are very easy to rec-
ognize due to their thick body, large
triangular-shaped head, and the rattle
on the tail tip (Figure 2). When I see a
rattlesnake in the field I recognize it im-
mediately with little question. However,
this was the first time I was fooled by a
gopher snake in thinking it was a rattle-
snake. The take home message: exercise
caution when dealing with mimics and
                                                                 Figure 2. Western Rattlesnake (Crotalus oreganus) from the Carrizo Plain,
                                                                                    San Luis Obispo County, CA. Photo by Howard Clark.

                                                                                                          SONORAN HERPETOLOGIST 25 (8) 2012           78

				
DOCUMENT INFO
Description: Clark, H.O., Jr. 2012. Rattlesnake mimicry in the Pacific Gopher Snake (Pituophis catenifer catenifer). Sonoran Herpetologist 25(8):78.