Our half-term holiday destination this year was Banff in Canada. A trip timed to coincide with the renowned Banff Centre Mountain Film and Book Festival where my partner, Heather, was a shortlisted author in the mountain book competition. Of course, for me, this was also an opportunity to see one of Canada’s most endangered animals among some stunning mountain scenery.

At this point I know that you are thinking along the lines of black bear, grizzly bear, wolf, moose, or perhaps lynx? Realistically you would need to spend more than a week there to have a chance encounter with any of these species. Many, but not all, of the bears are already hibernating. The species I got to see is far smaller, little bigger than an apple seed, and enjoys temperatures that are somewhat tropical all year round.

The freshwater snail Physella johnsoni, Banff Springs Snail, (pictured) has evolved to live in extreme conditions. Rain and snow melt percolates down through the mountain over the hill from Banff reaching hot rocks several kilometres below. Steamy waters are then forced upwards through a fault within Sulphur Mountain, one of the many peaks that tower above Banff, emerging at numerous hot springs. It is here that these small, air breathing, gastropods have made their home. They live on the waters edge where the temperature is between 30 and 38C, and feed upon the algae and debris within.

The Banff Springs Snail is now only found at a handful of sites. Water contamination caused by the hot springs being used for tourism over the years has led to a decline in locations where it can be found. Conservation measures, including a breeding programme, are now in place. The snail population varies dependent on the time of year and conditions. At times it is estimated that the entire population would fit within a coffee cup. Climate change remains a significant threat to the species. Without snowmelt there is potential for the springs to become dry.

The Cave and Basin National Historic Site is the best location to see the snails with boardwalks allowing easy viewing. When I visited, the snails were afloat on leaves that had fallen over the autumn. Take heed though, while the view of the snails and mountains from here are spectacular, the sulphur within the waters makes the aroma near the waters edge somewhat unpleasant. On occasion, some people find it a little too repulsive. While I was fine with the smell, I am not sure that I would have wanted to bathe in the waters here as tourists once did. These waters are best left to the snails.

wharfedale-nats.org.uk