New research shows that water, not shade, is a critical component to staving off heat exhaustion in moose
A bull moose pauses against the backdrop of the Teton Range on Oct. 5 in Grand Teton National Park. Moose need wet ground or standing water to plop their 800-pound bodies into in order to release potentially dangerous heat.
Christine Peterson, For the Star-Tribune
Moose are impressively well adapted to their landscapes. Legs almost 6 feet long allow them to pick through marshes and stalk through deep snow. Gangly necks help them reach willow leaves and aquatic vegetation. Dark hair helps them stay warm in frigid winters as far north as northern Alaska.
They are not, however, well adapted to heat.
In the gambit of problems facing moose across the northern hemisphere — from parasites and habitat loss to predators and ticks — researchers at the University of Wyoming wondered just how big a problem heat was to moose, and what the knobby-kneed creatures needed to cool down. So they launched a project several years ago in Wyoming’s Snowy Range to look at just that.
“For quite some time, I’d been really drawn to the notion that there’s other aspects associated with food and nutrition impacting our southern moose populations. They have issues with parasites and predators in some places, but in other places we don’t,” said Kevin Monteith, a UW associate professor. “Might coping with warming temperatures be one more contributing factor?”
What they found is not good news in the face of a warming, drying climate.
Moose do, in fact, need cool areas to slough off heat. But those areas can’t just be shady spots. Moose need wet ground or standing water to plop their 800-pound bodies into in order to release potentially dangerous heat. The conclusion was published recently in the journal Animal Behaviour, and another paper by UW PhD student Tana Verzuh will follow with even more specifics.
Monteith and Verzuh say while the news may be discouraging to moose and those who dream of hunting, photographing or simply stopping to stare at them on side of the road, the creature’s demise is not pre-determined. The paper’s results help give wildlife and land managers a goal: Maintain and improve riparian areas like wetlands and creek bottoms in order to sustain moose populations.
“You assume moose need water and thermal cover, but it’s good to know the importance of wet ground or standing water,” said Lee Knox, a Laramie regional biologist for the Wyoming Game and Fish Department. “We’re hoping, based off this information, that the large scale Mullen Fire that removed most of the thermal cover will still provide access to the wet bed sites and we will not see large scale population declines like we saw post Yellowstone Fire.”
Despite appearing to belong here, and gracing much our Wyoming’s tourist trinkets, Moose aren’t native to the southern part of Wyoming, or really the northern part, either. They evolved to live from the farthest north reaches of Alaska across to eastern Canada and down into the northern part of the lower 48 states. In the late 1800s and early 1900s, they migrated down to the northwest corner of Wyoming. But other areas in the state where they have flourished were either introduced directly or migrated from another introduced population.
And in many places, they’re struggling, Monteith said.
“The general trends overall are fewer and fewer moose,” he said. “When you look over a short period of time, we’re hanging in there, but if you look over a bigger period, if you look back two or three decades ago, it’s striking.”
The decline in moose in the northwest corner of Wyoming started long before the reinstruction of wolves and resurgence of grizzly bears, Monteith said. And many of the areas where moose are struggling don’t have the suite of large carnivores.
Moose farther east than Wyoming suffer from tick infestations and diseases like liver fluke and meningeal worm — parasitic larvae that lives in moose spinal cords and brains. Moose in Wyoming struggle with parasites like carotid artery worm and also ticks. Add habitat issues on top of that, as well as predation in areas with bears and wolves, and the future of moose can look bleak.
But Monteith and Verzuh wondered if something else was going on. Heat, they discussed, could be a prevailing issue because moose, much like dogs, can’t sweat.
“An elk can cover 90 percent of their body with sweat,” Monteith said. “With moose, you have this large-bodied animal with black hair, and when it gets heat stressed it pants like a dog, and panting is a very inefficient way to dump heat.”
So Verzuh spent three years tracking 30 moose with GPS collars that updated locations in real time to see where moose bedded down. She wondered if, during the heat of the day, moose simply needed shade to cool off, or if they needed something more.
In each area where a moose bedded, she followed up by installing mini weather stations in four locations for 24 hours and measured the soil moisture content. The mass of data allowed her to figure out what conditions moose looked for when choosing where to rest.
Unlike prevailing thought that moose only needed shade to cool down, she found after analyzing her data that they overwhelmingly chose wet areas during hot days.
“If you think about, when you’re going and laying down in the shade, you’re reducing the amount of heat you’re gaining, but you want to dump heat. Which you don’t necessarily enhance by seeking shade,” Monteith said. “On the other hand, you can lose a lot of heat by going in the swimming pool.”
What does this mean for moose in a world that’s warming and drying? It may mean, Monteith said, that without habitat interventions, moose numbers may well dwindle in the southerly portions of their ranges — places like the Snowy Range or even the Bighorns.
But it also gives a call to action for land managers and biologists. If moose require water and riparian areas to thrive, then agencies like the National Forest Service now know where to put effort into habitat treatments.
“How can we manage to preserve those habitats that are super beneficial for moose?” Varzuh said.
It may also mean a greater focus on restoring creatures like beavers into riparian areas to expand wetlands, Knox said. The result is not only good for moose, but also many other plants and wildlife that depend on cool, wet areas.
Data like this is critical for wildlife managers, Knox said, because “every moose manager is waiting, wondering, ‘when is the crash coming?’”
What matters then, is how to help stave off that crash.