Beavers Are Heat Wave Heroes
As explained below, beaver dams help cool the water — and the air. They also reduce wildfires.
NOTE: this article was originally published to Vox’s Apple News channel on July 22, 2022. It was written by Benji Jones.
Animals don’t have AC. But they have beavers.
During an intense heat wave, humans have a number of tools to stay cool, such as air conditioning, swimming pools, and ice cream. Wild animals, meanwhile, have beavers.
Yes, beavers. These web-footed, fat-tailed amphibious rodents help countless other critters survive a heat wave. They not only drench certain landscapes in cold water but also help cool the air. They even make forests and grasslands less likely to burn.
This is especially important right now. In the last two weeks, an oppressive heat wave has been roasting much of the US and Europe, putting both humans and wildlife at risk. The UK saw its hottest day on record. Temperatures in parts of Oklahoma and Texas hit 115 degrees. And there are still two months of summer left.
While beavers were once nearly hunted to extinction in North America and parts of Europe — and they’re still considered, by some, as pests — it’s increasingly clear that these animals help safeguard ecosystems against the wrath of climate change. Beavers are very much wildlife heroes in a warming world, and we’d be wise to follow the example they set.
Beaver dams help cool the water — and the air
The fact that most people know about beavers is that they build dams. But these structures are more than just a pile of sticks laid in a stream. They’re hydrological wonders.
Dams form ponds, widen rivers, and create wetlands, building all kinds of aquatic habitats that many other animals like birds and frogs rely on. That’s why beavers are often called ecosystem engineers.
More than just spreading water around, however, beavers also help cool it down.
Dams can deepen streams, and deeper layers of water tend to be cooler. As streams run into these structures, they can start to dig into the river bed, according to Emily Fairfax, an expert in ecology and hydrology at California State University Channel Islands. So there can be, say, a six-foot-deep pool behind a three-foot-high beaver dam, she said.
Dams also help force cold groundwater to the surface. Made of sticks, leaves, and mud, dams block water as it rushes downstream, forcing some of it to travel underground, where it mixes with chillier groundwater before resurfacing.
“That is really important for a lot of temperature-sensitive species like salmon and trout,” Fairfax says.
In one recent study, scientists relocated 69 beavers to a river basin in northwestern Washington state, and found that, on average, their dams cooled the streams by more than 4 degrees Fahrenheit (2.3 Celsius) during certain times of the year. Another study, published in 2017, saw similarly large drops in temperature after beavers built dams.
Remarkably, beavers can also help chill the air.
“If you’re standing near a beaver meadow, pretty much anywhere, it’s going to be way cooler,” said Christine Hatch, an extension associate professor at the University of Massachusetts Amherst.
As all that water in a beaver habitat starts to evaporate, the air cools down. That’s because turning water into vapor requires energy, and some of that energy comes from the heat in the air, Fairfax said. (This is how swamp coolers, or evaporative coolers, work; it’s also the same reason sweating cools the body down.)
“It’s like an AC system sitting out there in the landscape, keeping the air temperature, you know, 10 or 15 degrees cooler — which can make a big difference,” Fairfax said.
By inundating land with water, beavers can also create fire breaks
Intense heat waves can also fuel other problems like droughts and wildfires.
Beavers, again, can help.
There’s one obvious benefit that comes from beaver dams flooding the landscape with water: Wet things don’t burn as easily. “The plants are effectively irrigated year-round,” said Fairfax, who led a study published in 2020 that showed that areas full of beaver dams are “relatively unaffected by wildfire,” compared to similar but dam-less habitats.
“Beaver damming plays a significant role in protecting riparian [i.e., river-adjacent] vegetation during wildfires,” Fairfax and her co-author wrote in the study, titled “Smokey the Beaver.”
During wildfires, areas with beaver dams essentially can function as “a refuge for absolutely every critter that can get in there,” Hatch said.
And it’s not just fires. Beavers also provide insurance against droughts, by helping replenish the groundwater that humans rely on, Hatch said. Their dams generally slow water that’s traveling downstream, allowing it to percolate deep underground, where it’s less likely to dry up.
(By slowing the flow of water, beavers also help mitigate the severity of floods — yet another natural disaster that climate change can make worse.)
What a beaver can teach us about resiliency
So beavers are pretty darn great. By simply living their best lives — by damming up streams with their cute little hands and powerful buck teeth — they’re helping out so many critters around them. We should all be more like beavers, really.
We can learn from them, too. As the ongoing heat waves have shown, our built environment can’t withstand the consequences of climate change. Roads and railways are literally buckling. We need to make our cities and towns much more resilient, not unlike a habitat filled with beaver dams.
And these animals can help as we try to adapt to a hotter world, Fairfax said. “We’re not alone on this planet,” she said. “We don’t have to engineer solutions ourselves.”
Instead of just relying on human-made technologies and infrastructure, we can also restore species like beavers to the landscape. “They’re out there and we can definitely take advantage of that,” Fairfax said, though it will require “working with nature — instead of constantly against it.”