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The future is looking brighter for the threatened and obscure New Mexico ridge-nosed rattlesnake (aptly named Crotalus willardi obscurus), as partners come together to restore and repopulate a reptile so rare and hard to find in some populations it takes an on average over 800 hours for an expert to encounter a single snake.
鈥淭he name obscurus might refer to the fact that this subspecies can be hard to find and was discovered pretty late for an animal that occurs in the United States.,鈥� said Arizona State University Zoology Professor and leading ridge-nosed rattlesnake expert Dr. Andrew Holycross. 鈥淚t wasn鈥檛 described by science until the 1970s, and it was listed as threatened under the Endangered Species Act only a few years later. Obscurus might also refer to its faded pattern and less vibrant grayish coloration, as compared to the prominent markings and bright orangey browns of other ridge-nosed rattlesnake subspecies.鈥�
Save the Buzz Tails!
As venomous pit vipers (referring to the heat-sensing pit organs located between their eyes and nostrils), imperiled rattlesnakes are at a recovery disadvantage as they are often feared. In an effort to bring the subspecies out of obscurity and into recovery, biologists from the U.S. Fish and Wildlife Service have begun a new initiative with conservation partners, which all started around a campfire.
鈥淏iologists from the Service were invited to assist with annual rattlesnake field activities in the New Mexico bootheel a couple of years in a row,鈥� said Holycross, who is also a research associate with The Rattlesnake Conservancy. 鈥淒uring campfire conversations, they were wowed by our data set and also seemed impressed by our operations under harsh field conditions,鈥�
The conversation moved from admiration to talking next steps.
鈥業t was the genesis of discussions that have led to broader partnerships and this project in particular,鈥� said Holycross.
U.S. Fish and Wildlife Service New Mexico Ecological Services Field Office Biologist Clinton Smith, who has a background in herpetology, says the Service鈥檚 role in the recovery of the New Mexico ridge-nosed rattlesnake in the past has been very limited. However, there are ways for the Service to bolster the efforts of non-federal partners.
It Takes a Village
鈥淥ur academic research partners have had a heavier load with regards to basically everything for the rattlesnake,鈥� said Smith. 鈥淥ne of the things we did for this subspecies is work with our partners at the Rattlesnake Conservancy, and we put together a proposal for them to apply for Recovery Challenge funding. The Conservancy received the grant and are now assisting with activities that will directly help recover the species.鈥�
The Recovery Challenge funding program provides a unique financial assistance opportunity for non-federal partners 鈥� both new and longstanding 鈥� working on implementing high-priority recovery actions for species listed as endangered and threatened under the Endangered Species Act, as identified by the U.S. Fish and Wildlife Service in species recovery plans.
There are five objectives identified in the grant:
- Increasing the survey efforts where they鈥檙e known to occur in hopes of finding more rattlesnakes.
- Studying environmental factors important to the rattlesnakes (including temperature and humidity) across areas where the rattlesnake lives.
- To augment a genetically poor population in the U.S. partners have translocated 15 individuals from a larger population Mexico.
- Supporting captive breeding. To date, 30 individuals from Mexico have been brought in and given to three zoos to help with captive breeding for a recovery population.
- Increasing public awareness of rattlesnakes and their threats.
The Rattlesnake Conservancy calls this grant-funded, five-pronged initiative Project Obscurus.
Partners in Project Obscurus
While named for New Mexico, this ridge-nosed rattlesnake subspecies also occurs in Arizona. In both states, the state wildlife agencies are playing valuable roles in the recovery effort.
鈥淭he Peloncillo Mountains straddle Arizona and New Mexico, where habitat is a bit lower and drier,鈥� said Dr. Tom Jones, Ph.D., the Amphibians and Reptiles Program Manager for the Arizona Game and Fish Department. 鈥淲e suspect several things combined over the years have limited that population, and so it鈥檚 very difficult to find rattlesnakes there. There is a less bottle-necked population on a mountain range in southwestern New Mexico. Then down in the Sierra San Luis Mountains in Chihuahua and Sonora, Mexico, there鈥檚 a more numerous population within a bigger mountain range that is more genetically diverse. They appear to be doing better than the two populations in the United States. So, you have three different tiers of populations for this snake.鈥�
Mexico has also been a vital partner in this subspecies recovery, as most of the population of snakes lives there, along with all five ridge-nosed subspecies. Mexico is also home to some of the foremost experts in rattlesnake science. Ashabitat for the New Mexico ridge-nosed rattlesnake becomes drier and impacted by wildfire, conservation partners are considering every tool they can in the recovery toolbox to ensure its survival into the future.
鈥淗umidity plays a big role in the snakes health, particularly their shedding, and so drying out is a challenge for these animals,鈥� said New Mexico Department of Game and Fish Herpetologist Leland Pierce. 鈥淭hey need to be associated with routes and areas that have better humidity, and, if under the guidance of the U.S. Fish and Wildlife Service, because this is a federally protected animal, we need to look at perhaps placing this animal in areas that have more elevation and more habitat where it's not normally found, which would be assisted migration. We are certainly open to that discussion and to see what might come of it.鈥�
