Climate Change and Idaho Bears

Baily Hazzard

When we think of climate change, images come to mind of tiny ice patches near the north and south poles, or a raging wildfire in a forest far away, or smoke billowing out the towers of a big factory. It is difficult for many of us to think of this issue as close to home, in our little gem state, where our forests are lush and green. Here we experience the four seasons. We kayak and raft down our rivers that run cold and clean. We hike and bike upon our tidy mountain trails. Here in Idaho, we love the outdoors. 


It is difficult to see the immediate evidence of climate change in our own state. Yet the science shows that we are in fact seeing evidence of climate change and its effect on the ecosystems in Idaho. There are many species of wildlife which could be studied to observe these effects, and a few notable species who have already been studied are the bears of Idaho. Rising temperatures are affecting the grizzly bear and the black bear, resulting in many things such as changing hibernation routines, impacts on other wildlife species, and dangers posed to humans. 


The grizzly bear is known to go into a state of hibernation when food is scarce. And contrary to popular opinion, a grizzly bear or black bear does not go into hibernation due to the cold weather, but due to a lack of food. If food is scarce, they will go into hibernation early. If the temperatures increase, they may not go into hibernation at all. The Yellowstone grizzly bear is suffering from the impacts of a warmer climate which depletes their food sources. One example of this is a rapid decline in the whitebark pine in the Yellowstone national forest. This is a key fall food source for the bears. Grizzlies are omnivores and a large part of their diet consists of eating the whitebark pine nuts. When they are preparing for hibernation, eating high fatty foods such as this are essential. 


Predatory lake trout, drought, and other factors have resulted in a decline of the native Yellowstone cutthroat trout population, another important grizzly bear food source. A decline of the cutthroat trout population is having a trickle down effect on other species, as observed by researchers William Deacy and Jonathan Armstrong, ecologists with Oregon State University. The researchers found that grizzly bears who normally feast on fish from the rivers instead chose to eat from the elderberry bushes, which had ripened earlier in the year due to an unusually warmer spring. With the elderberry bushes ripening earlier in the year, the trickle-down effect is a decrease in food supplies for other animals. And so the results of this are harmful, as the researchers would find out, because previously bears would pull the fish from the river and leave much of the leftovers on the banks to be eaten by smaller animals such as foxes, weasels, and gulls. The remaining pieces of the fish carcass would then fertilize the soil. William Deacy is quoted as saying, “What’s a strangely warm year now will be the average. If that happens, we can expect to see the trickle-down effects being more permanent, and the other wildlife populations will probably be affected.” 


Scientists have observed the black bear altering their hibernation routines because of a change in temperature. Some of them are not hibernating at all or waking from hibernation too early.  A field study on black bears revealed “for every one degree Celsius that minimum temperatures increase in winter, bears hibernate for six fewer days” (Pierre-Louis). And if temperatures continue to rise globally, bears may stay out of hibernation by fifteen to thirty-nine more days per year by the middle of the century.


Research suggests that there are two factors that play a role in bears failing to hibernate altogether or hibernating for shorter periods of time. These two key factors are warmer temperatures and a resulting increase in food supply, which decrease the amount of time spent asleep. Warmer temperatures have not always resulted in an increased food supply. In years of severe drought, such as in 2014 and 2015 in Nevada, the food supply for black bears dropped significantly, leading to the bears going in search of human food, especially observed with black bears. This has been observed from an increase in the number of bear complaints made to the Nevada Department of Wildlife. Similar results are being observed in Idaho, where Fish and Game respond to more and more calls from citizens who report that bears have wandered onto their property where they begin eating from garbage cans, help themselves to bird seed, and enjoy food set out for pets. Bears are not to blame for going in search of food in human populated areas, as the expansion of our communities leads us closer into their territory and their habitats. Several of our mountain towns are located in bear habitat. If we consider this, along with the fact that bears can smell food up to five miles away, it is no surprise at all that they wander into the yards of many mountain homes. In addition to this, bears have great memories and will return to a home that has once provided them with food. 


There are many things that we can do to help tackle the issue of climate change in our own state. We can save the Idaho bears by acting now and by being a part of the conversation. We are already seeing proposals in the legislature to make changes. Idaho congressman Mike Simpson has proposed to remove four of the dams on the Snake River. One resulting effect from the removal of these dams is the restoration of endangered salmon, a key food source for Idaho bears. You can read up on this proposal and show your support in many ways: by becoming a part of the conversation, spreading awareness, helping others to understand the issue, sharing the information on social media, or even voting to show your support. 


I attended a virtual Facebook live event, hosted by the Idaho Wildlife Federation, where this proposal was discussed by five panelists with a wide range of expertise. I wanted to attend the event so that I could better understand the relationship between dams, rivers, and bear habitat in light of climate change. It should first be noted that “removing” these dams does not mean that the dams will be physically removed, only turned off. The concrete structures will stay in place and could be turned back on if necessary. 


Though the conversation mainly focused on what it would look like for these dams to be turned off and how this would increase salmon populations in the Snake River, I asked a follow up question about how the decrease in fish like salmon and cutthroat are having an effect on other species such as bears. Garrett Visser elaborated on this. "In general, the lack of anadromous fish and resident salmonids does have an effect on other aquatic and terrestrial species and forests overall,” he said. “Salmon carcasses contribute to the overall health of forests. When fish cannot be captured and incorporated into the trophic system, that has impacts on forest growth and ecological function in which species like bears need to thrive. And of course--if available, bears will consume fish as part of their diet. Without fish, bears are finding food sources in other places." It is clear that the return of salmon and other fish to rivers is an important part of the overall health of the ecosystem, which benefits both grizzlies as well as black bears. In connecting this to climate change, this illustrates how fragile the ecosystem is. When one part is stressed, another is too. Removing dams as a climate change solution might sound like a stretch to some, but it is part of a multi-pronged approach to support a thriving habibat. 


There are other things we can do to show support and get involved. We can donate to local groups such as the Nature Conservancy in Idaho, which aims to spread awareness and start conversations about the issue. They host climate change projects and challenges that motivate business owners and political leaders to act, and also to identify policy solutions that are key to their Climate Action Initiative. There are many websites that you can visit to read more about these initiatives or sign up to volunteer your time. 

Works Cited

Barcott, Bruce. “Polar Bear Cubs Drowning Due to Sea Ice Loss, Says Report.” The Guardian. 19 July 2011.

Beitler, Jane. “Younger Sea Ice and Scarcer Polar Bears.” NASA. 15 Oct. 2020.

McGrath, Matt. “Polar Bears Fail to Adapt to Lack of Food in Warmer Arctic.” BBC News, BBC, 16 July 2015.

Pidcock, Roz. “Polar Bears and Climate Change: What Does the Science Say?” Carbon Brief, 18 July 2017.

Zuckerman, Laura. “Polar Bear Numbers Seen Declining a Third from Arctic Sea Ice Melt.” Reuters, Thomson Reuters, 13 Dec. 2016, .


Other source material that informed this article: 

Barker, Rocky. "This GOP Congressman Wants to Remove 4 Dams to Save Idaho's Salmon: It'll Cost Billions." Idaho Statesman. Feb 6, 2021.

Osborn, Vicky. "Living with Black Bears." Idaho Fish & Game. June 3, 2019. "Tacking Climate Change in Idaho." Oct 26, 2020.

EPA. "What Climate Change Means for Idaho." August 2106.

Baily Hazzard is currently pursuing a degree in English Literature at Boise State University. She enjoys reading, writing, and sketching. In addition to conversations about topics such as climate change, human rights, and animal agriculture, Baily enjoys hiking and biking Idaho trails.

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