n Spring of 1998, I began soliciting photographs of snakes from Grand Canyon, particularly along the Colorado River corridor from Glen Canyon Dam to Hoover Dam. I am hoping to utilize the photographs to gain a better understanding of the distribution and types of snakes within the Grand Canyon region.

My interest in the distribution of snakes in the canyon was sparked by a photograph of a rattlesnake that a colleague took in the canyon in the fall of 1997 (while it was eating a song sparrow). The assumption was that the rattlesnake was a Grand Canyon pink. Yet, when shown to Cecil Schwalbe, a herpetologist at the University of Arizona, he identified it as a speckled rattlesnake. He also mentioned that the lack of documentation of species identification (i.e. specimen or photo vouchers) has resulted in a very incomplete understanding of distribution of snakes in the canyon.

There are potentially 22 species of snakes, including up to six species and subspecies of rattlesnakes along the Colorado River within Grand Canyon (Miller et. al. 1982, C. Schwalbe pers. comm.). There seems to be a general assumption, of which I too was initially guilty, that all rattlers in the canyon are Grand Canyon pinks (Crotalus viridis abyssus), a subspecies of the western rattlesnake (Crotalus viridis). Most people of the river community I have spoken to regarding the presence of speckled rattlesnakes (Crotalus mitchellii) in the canyon were unaware that this species existed there. Even the Amphibians and Reptiles of the Grand Canyon (Miller et. al. 1982) considered the speckled rattlesnake to be rare and only had one record for it (Emery Falls, 1975). However, since I started this project in April 1998, I have obtained an additional six records of this species, including one as far upstream as Deer Creek (rm 136r).

The subspecies of the western rattlesnake can be difficult to determine and hybrids may exist. Including the variable coloration, the speckled and the western rattlesnakes can look very similar. The latter was demonstrated by a recent (1998) Smithsonian publication, Rattlesnake: Portrait of a Predator by Manny Rubio, where the title page photograph is of a speckled rattlesnake, but was misidentified as a Grand Canyon pink. Apparently, this snake was recently on display at the Arizona-Sonoran Desert Museum as such. Because some of these species and subspecies may look similar, photographs are the best tool for identifying the snakes. Photographs allow for a verifiable form of identification. Apparently, this method of documentation was used to gather additional information for the Amphibians and Reptiles of the Grand Canyon (Miller et. al. 1982). Since the initiation of this project, I have received photographs and slides of an additional 32 records of snakes in the canyon. These additional records substantially increased the number of known records of a few snake species, such as the speckled rattlesnake.

With your assistance we can learn more about the resources in the canyon. I would appreciate it if you would assist with the collection of even more records on the snakes and other reptiles in the canyon. I have included a data sheet specifying the information of interest. Please feel free to copy and pass the data sheet on to passengers or other colleagues in the field who might be able to contribute to this project.

Snakes of the Grand Canyon Identification and Distribution Project: Data Sheet

Date (M/D/Y):

Time (of observation):

Observer(s):

Contact address and phone:

River Mile and Side: Location name (if any):

Type of habitat (i.e. in the tamarisk, under/on a rock(s), on the beach, on the talus, on the trail, etc):

Location to river (estimated distance from it): If the location was on a trail, please specify:

Provide any additional information below: (such as general color of snake, in case it does not show in photo/slide; layer of rock formation where it was found; behavior, etc.)

P.S. If you want a response regarding the identification, please just ask and provide a return address (snail mail or e-mail). Thanks for your contribution to our knowledge of the reptiles in the Grand Canyon.

Nikolle Brown