JACKSON, Wyo. — After a record-setting winter last year that put severe stress on a number of local species, particularly mule deer, the low temperatures and snow have returned and the Old Farmer’s Almanac is predicting another cold winter for Wyoming’s 2023/24 season. This would be good news for the moose population, who thrived last winter.
According to Aly Courtemanch, wildlife biologist with the Wyoming Game and Fish Department (WGFD), the mild temperatures two winters ago correlated with a substantial number of moose dying around the valley. This included a few from the collared moose program in addition to non-collared moose and calves.
Based off the necropsies done on the moose carcasses, the warmer winter showed an increase in the severity of tick infestations in moose and moose calves. The data also revealed the adult moose were in poor health and showed a lot of kidney issues, Courtemanch tells Buckrail, pointing to chronically poor diets and chronic stress for these animals.
However, that turned around this past winter, when the WGFD observed that the local moose population was doing much better in the harsh weather than they had in the couple previous, milder years.
“It’s counterintuitive,” Courtemanch says. “In this past winter that was so severe with cold, deep snow, moose actually did great. Those are the conditions that they thrive in; we find that they do worse in these warmer, drier winters where there’s not much snow and it’s hot for them.”
Because moose are evolutionarily adapted to cold weather, they don’t deal with heat well. Courtemanch says their large bodies, dark coloring and thick winter coat can contribute to their tendency to attract and hold heat, making overheating easier for this species than other local ungulates.
Courtemanch calls the temperature threshold for moose “striking.” According to her, in the summer, moose start to get heat-stressed once the temperature rises above 59 degrees Fahrenheit. In the winter, with their heavy winter coats, moose become heat-stressed in temperatures over 23 degrees Fahrenheit. When heat-stressed, moose stop feeding to lay down in the shade, compromising their caloric intake.
“They just didn’t evolve in these warmer climates, so they can’t really handle it,” Courtemanch says. “Climate change is not good for them.”
Mark Gocke, public information specialist with the WGFD, emphasizes that Jackson Hole is at the southern end of moose range, a very critical place to see the impact of a warming climate.
Research published in Scientific American looking at moose in Maine highlights a similar death trend on the population’s southern range. Scientists there are suggesting both young and adult moose are suffering from new diseases and parasites, including winter ticks, as the climate warms. Additionally, an even more recent National Institute of Health (NIH) study confirms moose on the bioclimatic edges of their range are particularly vulnerable to stress caused by environmental alterations associated with climate change, and are exhibiting population declines and range contractions along southern geographic extents.
Jackson Hole’s current moose population is down 70 percent from what it was in the 1980s. The Jackson Hole Conservation Alliance notes that in addition to disease, malnutrition and stress, climate change is increasing the frequency and severity of wildfires that destroy habitat.
So if this upcoming winter does prove to be a long and cold one, it will be a good thing for the moose. Grand Teton National Park Foundation (GTNPF) emphasizes that moose adaptions to deep snow include long legs for efficient movement and a highly developed sense of smell to find nutritious parts of shrubs hidden under the snow. Behaviorally, moose calves remain with their mothers through winter and follow behind them so they don’t have to exert extra energy breaking trail.
Even with adaptations for survival, though, GTNPF urges everyone to consider the space and energy conservation needs of wildlife as the winter hits. Giving moose a brake is also critical all times of year; the WGFD cites research that shows slowing down by just five miles per hour can significantly increase a driver’s reaction time to avoid wildlife-vehicle collisions.
