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91��ý alumnus Emily Fairfax shared her scientific expertise as the beaver consultant on the new Pixar film��Hoppers

Emily Fairfax came home one evening from her job as a weapons engineer at Los Alamos National Laboratory feeling a bit sad. Yes, she was using her degrees in chemistry and physics, but the work just wasn’t a good fit for her.

She sat on the couch and turned on the TV, happening across an episode of Nature on PBS called “

“I was so hooked,” recalls Fairfax (PhDGeol’19). “I couldn’t stop thinking about it. There were all these aerial images of beaver wetlands in places like the Nevada desert, which was amazing and I couldn’t get it out of my head. So, I thought, ‘I’ve got to go to grad school and study beavers.’”

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91��ý alumnus Emily Fairfax (PhDGeol’19) was the scientific beaver consultant for the new Pixar film Hoppers. (Photo: Emily Fairfax)

Fast forward to the evening of Feb. 23 on the red carpet outside the El Capitan Theatre in Hollywood, California. There, wearing a beautiful teal and black dress with a lace and sequin overlay—and having received glam tips from her grad students—Fairfax posed for photographers in front of a yellow screen bearing the images of animated beavers she’d helped bring to life.

Fairfax, whose “a-ha beavers!” moment led her to the University of Colorado Boulder Department of Geological Sciences, was the scientific beaver consultant for the acclaimed new Pixar film Hoppers, which opened nationwide Friday.

The story of an animal-loving college student whose mind is transferred into a robotic beaver so she can help save a pristine glade from being paved for a freeway, Hoppers highlights a keystone species in a scientifically accurate way that is, frankly, adorable.��

“People need to know that they’re a keystone species,” says Fairfax, who signed on to the film project with the assurance that this point would be emphasized. “When you lose the beaver, you lose the ecosystem, and I think (Pixar filmmakers) made that crystal clear.��

“The other point that I really wanted to be in the film is that beavers are not just off in national parks. You can have beavers living in cities, living adjacent to cities, and we can coexist with them to our benefit, not just the benefit of the beaver. I wanted to highlight the idea that protecting beavers and habitats isn’t just about protecting nature out of the goodness of our hearts; we benefit greatly.”

The force of a glacier

Long before her pivot from Los Alamos to 91��ý, Fairfax, who now is an assistant professor of geography, environment and society at the University of Minnesota, was a Girl Scout in a troop that took its role as stewards of the natural world very seriously.

“We learned the basic principles of ‘Leave No Trace’ very early on, but then our troop leaders took it a step further,” she wrote on her personal website. “They urged us to put in that little bit of extra effort and leave things��better��than we found them. When we went camping this usually panned out as picking up trash off of trails, but the sentiment stuck with me. If everyone strives to leave things better than they started—even if only by a little bit—then the overall state of things will consistently improve.”

It’s a sentiment that dovetailed neatly with her graduate work at 91��ý, where she studied beavers through the lens of ecohydrology, combining remote sensing, modeling and field work to understand how beaver damming changes the landscape and the timescales on which that change happens.

“I’m at heart a water scientist—how fast it’s moving, if it’s being slowed or stored or just blasting downstream superfast,” Fairfax says. “I care about the shape of rivers as a geomorphologist, and I’m very hyper-focused on how one specific animal controls water or the shape of water.”

Her first Colorado field site was in Lefthand Canyon west of Boulder—where, if you drive slowly and look closely, it’s possible to see an 11-foot-tall beaver dam from the road—and her dissertation research was inspired by “Leave It to Beavers”: “In the documentary, they were interviewing hydrologists and geomorphologists, who kept bringing up how beaver wetlands in these areas are the only things staying green during droughts.��

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Emily Fairfax takes measurements of a beaver dam in Lefthand Canyon west of Boulder. (Photo: Emily Fairfax)

“I get that beavers can seem really chaotic—they don’t draw any blueprints, they don’t pull permits, they don’t let anybody know what they’re going to do before they do it. But beavers are second only to us, humans, in terms of animals that can change the physical earth. They’ve been damming for at least 7.5 million years, maybe as long as 25 million years, so thinking about beavers as this geological force is really intellectually exciting—this rodent in my yard carries the force of a glacier.”

Inquiry from Pixar

Two years after earning her PhD and joining the California State University Channel Islands��faculty, where she worked before joining the University of Minnesota faculty in 2023, Fairfax presented a Zoom webinar about beavers and drought in California that several Pixar employees attended. “I thought, ‘OK, cool, they have a right to be interested in what’s going on in their state,’” she remembers. Several months later, she received an email with the subject line “Inquiry from Pixar” and thought it was a prank.��

Nope: It was legitimate.

Pixar filmmakers wanted her to give a presentation to studio staff about beavers, which she did. It turns out that Pixar was making a film about them, and after signing reams of non-disclosure agreements and securing a promise that the filmmakers wouldn’t even think about having the beaver characters eat fish—because beavers do not eat fish—Fairfax was officially the Hoppers beaver consultant.

At first, Fairfax answered a lot of basic questions about beaver behaviors, ecology, what they can and can’t do, how long they live, their family units, their size and why their teeth are orange. Then the questions started getting more specific: What other animals would you see in a beaver wetland? How do beavers get along with humans? If someone tried to build a road by a beaver wetland, how would beavers react? She brought a group of Pixar filmmakers to Lefthand Canyon for a week of beaver observation, which yielded even more questions.

“At every step along the way, they were turning seemingly disconnected beaver facts into scenes,” Fairfax says. For example, as with humans, beavers’ tailbones tuck under, allowing them to sit on their tails like little chairs. So, the scene in Hoppers in which the real beaver George sits on his tail is accurate, and the fact that the character Mabel sits with her tail outstretched is a clue that she’s not a real beaver.

The dam-building sequence in Hoppers is also scientifically accurate: “A lot of people don’t know how beavers build dams,” Fairfax explains. "It can be very sudden, and they will often use relatively large cobbles and stones to start, which they put along the base of their dams. Then they’ll put on some sticks and then pack it with mud. Everyone thinks they pat the mud on with their tails, but they actually use their paws. So, the sequence in the film where you see these super buff beavers lifting up stones and rolling them down, then you see other beavers waddling in carrying mud and patting it down, that actually shows the real sequence of dam building.”

Throughout the filmmaking process, Fairfax received scenes to review, so the accurately rotund beavers in the film are her doing. “The very first time I saw one of the (film) beavers, I told them it was too skinny. Beavers are shaped like a bowling ball, so when I saw it again it was a little fatter, and then I saw it again and it was a little fatter. Finally, people with Pixar were like, ‘If it’s sitting on its tail, it needs more rolls’ and ‘It should be jiggling more when it’s running.’ I was like, ‘Oh my god, this is adorable.’ They’re like big, fuzzy bowling balls, and I’m collecting all the little plushies.”

Science and storytelling

Through the process, Fairfax says, the filmmakers balanced storytelling and science. There were times when total accuracy had to concede a little to the story, “but they always asked me, ‘Is this realistic enough? Is it going to hurt beavers, is it going to hurt climate change work if we do it this way?’ They were always really good about asking me how much certain things mattered, because they are people trying to create a compelling narrative, but they also wanted to respect the science.”

(And speaking of respecting the science—and scientist—the full name of the film character Dr. Sam is Dr. Samatha Emily Fairfax.)

Fairfax’s work on the film was also a matter of balancing the often solitary, generally unglamorous work of science with the razzle-dazzle of Hollywood. She jokes that she considered wearing her waders to the Hollywood premiere, but her grad students stepped in with hair and makeup tips. And then she was on the red carpet with A-list stars like Jon Hamm, then inside the ornate theater watching the velvet curtain rise on her research via Hollywood movie magic.��

“It was just so surreal,” she says. “I’d seen the movie many times before that, but it was so real in that moment, packed into this theater, all the voice actors there, and immediately I’m crying. In many ways, it felt like there was a lot of myself on that screen, and seeing people’s reactions to it felt like seeing reactions to my research.

“Trying to translate what I know in a way that’s relevant to artists was not a normal part of my job, and it felt very high risk at first because what if people don’t like the movie and it sets beavers back? Beavers are still coming back from the fur trade, plus we have the rising challenge of climate change, so it felt risky. But it’s a beautiful movie and people seem to love it, so that makes me feel very hopeful about how science and storytelling can benefit all species.”

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