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A young western rattlesnake, Crotalus oreganus. Photo: Connor Long

URBAN VIPERS 2: Western rattlesnakes of Osoyoos, B.C.

Posted onAugust 5, 2021byOjibway Massasauga|News and Events, Ojibway Prairie Reptile Recovery, Urban Vipers

Welcome to another installation of our Urban Vipers series! In this blog, we’ll be discussing the population of western rattlesnakes (Crotalus oreganus) living in and around Osoyoos, British Columbia, with a special focus on the Osoyoos Indian Reserve, and how members of the Osoyoos Indian Band have worked to protect, and spread positive messaging about these wonderful snakes.

The Species

Crotalus oreganus is a snake of many names; depending where you are, it may be called the northern pacific rattlesnake, the southern pacific rattlesnake, the Grand Canyon rattlesnake, the midget faded rattlesnake, or the great basin rattlesnake. These five different names actually reflect the five-known subspecies of the western rattlesnake, a venomous snake ranging from Mexico’s Baja California Peninsula in the south, north to British Colombia, and west to Colorado. The only subspecies found in Canada is the Northern Pacific rattlesnake (Crotalus oreganus oreganus), and its Canadian range is restricted to the Thompson-Okanagan Interior of BC. The Canadian population size is estimated at 17,375 adults and juveniles spread across 368 known dens (Kirk et al. 2016).

Like other rattlesnakes, the western rattlesnake is ovoviviparous (producing young by means of eggs which are hatched within the body of the parent). In Canada, females give birth to 2-8 live young once every 3-4 years at their den site, where the young will spend at least their first winter. The snakes will emerge from hibernation as early as March, and are known to migrate as far as 4 km from their dens to reach their summer foraging sites! Unfortunately, these long seasonal migrations can be quite risky for the snakes, especially if they must cross roads. Road mortality is one of the primary threats to western rattlesnakes in BC (Snook and Blain 2012). Western rattlesnakes are listed as Threatened by COSEWIC due to expanding human activities in their habitat, resulting in road mortality, genetic isolation, disturbance or destruction of hibernation sites, and intentional killing.

The Locale

Range of the Northern Pacific rattlesnake (Crotalus oreganus oreganus) in southern British Columbia (dark gray). Adapted from COSEWIC report.

Osoyoos is a town located in the Okanagan Valley in British Colombia. This small town is home to around 5,000 permanent residents, and the population expands greatly in the summer months due to tourism. Visitors come to enjoy the warm Lake Osoyoos, beaches, resorts, wineries, and golf courses. For nature-lovers, the local desert-like ecosystems are a wonder to behold. The landscape includes dry forest, hills, valleys, and the semi-arid antelope-brush ecosystem, one of Canada’s rarest habitats. Bordering the Town of Osoyoos is the Osoyoos Indian Reserve (OIR). Stretching north to the town of Oliver, the OIR covers more than 120 km2 of land and is home to the Osoyoos Indian Band (one of the 7 communities which make up the Syilx people of the Okanagan Nation). Over 400 band members live and work on the OIR, and also share their land with rattlesnakes! Seventeen percent of all known western rattlesnake dens in Canada are located on Indian Reserve land – assuming an average den size of 47, that equates to ~3,000 snakes. Although the Osoyoos Indian Reserve is largely undeveloped and provides plenty of suitable snake habitat, rattlers will journey into the more heavily populated and cultivated area in and around Osoyoos.

Left, a view of Osoyoos, BC. Photo courtesy of Destination Osoyoos. Right, Spirit Ridge Resort in Osoyoos, overlooking a vineyard. Photo: Nk’Mip Desert Cultural Centre

The Methods

Luckily for these snakes, the Osoyoos Indian Band is committed to protecting them. Biologists at the Nk’Mip Desert Cultural Centre in Osoyoos conduct radio-telemetry studies of western rattlesnakes and Great Basin gopher snakes (a.k.a. bull snakes). This rattlesnake research program allows researchers to track the movement of snakes across the landscape, and helps identify their critical habitats (i.e., dens, summer foraging areas, and gestation sites). A population study that began in 2003 includes over 700 snakes!

Public outreach and education are another vital part of saving at-risk rattlesnakes. The Nk’Mip Desert Cultural Centre offers interpretive programs, public presentations, and nature trails, and also displays cultural exhibits and provides educational programs on the rich culture of the Okanagan people. The Centre also houses a nature exhibit, which features a live western rattlesnake and Great Basin gopher snake. The Centre’s ‘Adopt a Rattler’ program provides donors with a certificate of adoption, a one-on-one meeting with a biologist, a behind the scenes look at a PIT-tagging procedure, or end-of-season reports, depending on their donation level.

The Cultural Centre works with local businesses, as well, to promote species-at-risk-friendly land practices. These include the installation of snake barrier fencing, and use of artificial cover objects to reduce human-snake conflict. The artificial cover objects provide places for snakes to bask and seek shelter in locations away from human activity, and the fences prevent snakes from crossing onto the roads where they are likely to be hit, or into vineyards and resorts where they may encounter people. As part of this program, the Nk’Mip Desert Cultural Centre also trains employees of local resorts, campgrounds, and other businesses where snake encounters are likely, on how to safely handle and translocate reptiles a short distance out of harm’s way. Rattlesnake bites are more common when snakes are handled improperly or harassed by people, so programs like this can help to keep both snakes and people safe!

Many others are also working hard to protect the western rattlesnake in and around Osoyoos and the greater Okanagan Valley! The Okanagan Similkameen Conservation Alliance (OSCA), for example, provides information on living alongside snakes, and runs the ‘Snake Smart’ program which helps eliminate the negative public perceptions of snakes. Also, past research by WPC’s Stephanie Winton resulted in the installation of five new ecopassages by the B.C. government!

Final Thoughts

Without the hard work of the Nk’Mip Desert Cultural Centre staff and the other committed researchers, naturalists, and conservation organizations of the Okanagan Valley, the status of the western rattlesnake in southern BC would undoubtably be much worse. In Osoyoos it’s clear that research, human-snake conflict mitigation, and education are the three vital aspects to urban viper conservation and management. Looking back to the Boston and Lethbridge cases, a pattern appears to be emerging… With knowledge comes a healthy respect for venomous snakes, both of which form the foundation of a relationship allowing us to live alongside one another without conflict.

“In the end we will conserve only what we love; we will love only what we understand; and we will understand only what we are taught.”

Baba Dioum
Senegalese conservationist

Learn more

Urban Vipers 1: The Prairie Rattlesnakes of Lethbridge

Urban Vipers 3: The black mambas of Durban, South Africa

Urban Vipers 4: The jararacas of São Paulo, Brazil

Kelly Antaya

Field Technician – Ojibway Prairie Reptile Recovery

Kelly started working with Wildlife Preservation Canada as an intern, and is now a field technician. She has worked in reptile conservation throughout Ontario, and has also assisted on population studies of skinks and snakes on islands in northern Madagascar. Kelly is a graduate of Fleming College, where she received her diploma in ecosystem management.

Jonathan Choquette

Lead Biologist – Ojibway Prairie Reptile Recovery Program

Jonathan manages the recovery program for the Ojibway population of the massasauga rattlesnake in Southern Ontario. Jonathan’s research interests lie in the field of urban herpetology, having studied both biology and landscape architecture at the University of Guelph. Jonathan has authored or co-authored numerous reports and publications about the conservation of Canadian reptiles and amphibians in urban environments.