Fear, Discovery, and Animal Crossing

Once upon a time, long, long ago, I was a college student studying biology with plans to go to grad school somewhere to study ecology and possibly animal behavior. I was frustrated with the small scale of research one had to do as an undergrad, and I was looking forward to digging into something better. For example, I’d spent a lot of time tracking fishers and mink in New Hampshire in my teens, and Indiana, where I got my BA in biology, didn’t really have fishers. Since the two species have overlapping territories and prey, it seemed likely that without the larger species to compete with, mink in Indiana would have more opportunities for larger prey, and would thus have some evolutionary pressure to embiggen across the generations.

My plan to study this using the animals tracks. This would have been far cheaper and less invasive than trying to catch, weigh, and measure a representative sample of mink in two different parts of the U.S., and while the more invasive study might be necessary to fully support my hypothesis, tracks would certainly be enough to provide solid justification for such a study. I’d learned how to build a “trap” to collect tracks using aluminum foil, contact paper, and wood, so the material end of things would have been pretty straightforward to put together, and it’s a technique that gives you quite consistent data, by baiting the animals to use consistent behavior in a fairly controlled setting. I was also told that was much too big of a project for undergrad work. I suppose I can see why, but I still wonder whether I would have taken a different path had I been able to go through with it. The research I did end up doing primarily taught me that the shrews living in east-central Indiana had somehow figured out how to avoid drift fences and pit traps. It’s accurate to say I’ve done research on shrews, but over about a month of setting out research-supported live traps, and checking them multiple times per day, my partner and I didn’t catch a single damned shrew.

All of this is to say that I have a long-standing interest in both animal ecology, and animal behavior, as well as the various aspects of conservation, environmentalism, and so on. Writing this now, I’m honestly very tempted to do a little track survey around Dublin’s rivers, just for the fun of it. Maybe if I get enough patrons that I can afford the materials, I’ll start doing research projects and writing about them here.

There are a lot of reasons why this kind of research is good. The first, of course, is the same reason I support most other research – it’s a process of exploration. There might be nothing on the other side of that mountain but more forest, just like this side, but we won’t know that, until someone actually goes and looks. And once we know what’s on the other side of the mountain, well, that opens up a new frontier that also needs to be explored. Sure, you might just discover that your shrew-catching methods need to be updated, but you might also discover that the reason why horseshoe crab blood coagulates in that particular manner, is a chemical reaction that would make that blood a pillar of modern medicine, while also raising a number of ethical and environmental questions that go well beyond the scope of this paragraph.

Part of my discomfort with the horseshoe crab situation comes from my understanding, born of both observation and study, animals are, in some ways, just like us. There are a great many differences of course, some of which matter a lot, but they’re not just meat automatons wandering through the world until we find a use for them. They’re made of the same stuff as us, and their behavior is often guided by the same chemical reactions as the ones going on in your brain as you are reading this.

There’s a recording from a radio show that’s been kicking around the internet for a while, in which a caller complained about the placement of deer crossing signs. Wouldn’t it be better, she asked, to put the signs in lower-traffic areas, to reduce car crashes? She’d somehow gotten it into her head that the sign was there to tell deer where to cross the road, rather than to warn humans that deer often crossed in that area. It’s a kind of mental slip that I think most of us have had at some point in our lives, but we’re generally lucky enough to not have it happen on radio for everyone to hear.

The thing is, while there’s zero chance of literacy in white-tailed deer, she’s not wrong to assume some level of agency. Deer have reasons for the things they do. They have reasons why they cross the roads we build, why their timing seems to be so terrible sometimes, and why they will sometimes just stand and stare at those weird pair of bright lights that seems to be growing. Whether your concern is for deer or for humans, understanding those reasons is key to reducing those crashes. The deer don’t seem to have the capacity to understand us, and work around the weird shit we do, and they certainly don’t have any power over our actions as a species, which means that it’s on us to figure out how to make things better.

Enter the wildlife crossing.

The image shows a highway cutting through a dense, green conifer forest. In the background, behind he road, you can stony mountains looming over the river valley the road is following. Near the center of the photograph, there is a wide bridge over the highway. The bridge, a wildlife crossing, is covered in grass, shrubs and small trees, forming a “natural” pathway for wildlife to cross the highway.

Wildlife crossings, both with and without fences to guide animals toward them, have proven to be beneficial in reducing collisions, and in allowing more natural movement of animals:

The findings of the MSU genetics study, which collected some 10,000 hair samples from  and grizzlies, have been published in the British journal Proceedings of the Royal Society B, and a photograph of one of Banff’s wildlife overpasses is featured on the publication’s cover.

“Showing that the black  and grizzlies using the crossings to traverse the highway are also breeding is a major finding,” said former MSU graduate student and WTI scientist Michael Sawaya, who wrote the paper as the final piece for his doctorate in ecology. “While there have been a lot of studies showing that wildlife are using these crossings, this is the first time anyone has shown that animals using the crossings are breeding often enough to ensure that the populations on either side of the highway are not being genetically isolated.”

MSU professor of ecology Steven Kalinowski, who was Sawaya’s doctoral adviser and co-authored the paper, agreed that the genetic evidence offers the best indication to date of the success of Banff’s system of wildlife crossing structures.

The crossings – there are currently 44 in all – form the most extensive system of wildlife crossing structures on the planet. In addition to reducing collisions, the crossings project was designed to prevent fragmentation of wildlife populations living along Canada’s busiest highway. Grizzly bears, Banff’s marquee predator, are often negatively impacted by roads, Kalinowski added, so any true measure of the project’s success has to account for the impact on that population, which the Alberta government currently lists as threatened.

“These wildlife crossing structures cost millions of dollars and this is one of the first studies that has shown that they are doing what they are intended to do,” Kalinowski said. “If the bears aren’t crossing the road and breeding, you’re going to have fragmented and inbred populations on each side of the road.”

This is a good solution, and the kind of thinking I’ve always liked. My vision for a better world involves a lot of interweaving – in this case literal – of human and “natural” systems. Another version of these crossings that I would say is equally important, and far cheaper to build, is tunnels under roads, primarily for reptiles and amphibians, who tend to move seasonally in large numbers, and often get run over.

The thing is, as the radio caller from earlier eventually realized, we can’t just put up signs telling animals where to cross. We have to figure out where the heaviest animal traffic is, and build crossings there. Many such installations also use fences to guide animals to the crossing, similar to how I tried to use them to guide shrews to my bucket traps, but the ideal is to arrange things so that animals need as little direction as possible. This means, of course, that the research is ongoing. These animal crossings have worked quite well, but there’s still room for improvement. It turns out that some deer and elk, entirely reasonably, are suspicious of these bridges that we’ve built for them. We climbed the mountain, so to speak, and part of what’s on the other side is a bunch of frightened even-toed ungulates.

For the study, Abelson and Blumstein worked with UCLA undergraduate student Mehdi Nojoumi to review a set of nearly 600 animal-activated videos collected by Montana State University road ecologist Anthony Clevenger that showed elk and white-tailed deer in the vicinity of a Trans-Canada Highway wildlife undercrossing near Banff National Park in Alberta. Nojoumi observed the behavior of the animals before and after vehicles passed and counted the vehicles.

The videos showed that elk and deer on the roadside near the tunnel often shifted from foraging for food to fleeing or becoming vigilant after vehicles passed; those animals that showed fear or vigilance were much less likely to use the crossing. If they continued grazing when vehicles passed, as some did, they were more likely to use the crossing.

Surprisingly, the animals reacted more strongly when vehicles passed infrequently than when the traffic flowed steadily.

“We are not certain why animals are more responsive to fewer vehicles,” said Abelson, who is now a research scientist at the University of Texas at Austin. “It is possible that when there are many cars barreling down the road, they can be heard from farther away and don’t surprise the animals as much.”

The study reinforces that animals respond dynamically to human activities in ways that can influence if and how they use wildlife crossings. Abelson pointed out that some animals, like racoons, may be so accustomed to human activities that they don’t respond negatively at all, while others may be much more cautious. Behaviors differ from species to species, he stressed, and further research can help reveal these species-specific patterns.

“If we can figure out ways to leverage wildlife behaviors, we may be able to make wildlife crossings more effective,” Abelson said. “For example, walls to dampen sound or to reduce the visual effects of passing headlights may encourage use of crossing structures. We hope that this this study is just one of many that will examine different wildlife species and levels of traffic to better develop tools that increase the use of crossing structures by wildlife and, ultimately, protect the lives of humans and wildlife.”

To me, it seems like more steady traffic is less frightening because of its constancy. There’s a clear pattern of the loud things zipping by without regard for any of the animals around. If there’s nothing at all, and then suddenly there’s a car, that’s a break in the pattern – a new creature on the scene. When I lived in the country, I was much more aware of cars going by than I am in the city, and as I’ve said, I don’t think animals are all that different from us. Regardless, some of the differences that do  exist are pretty big, and we never know when we’ll find something unexpected, so as the scientists say, we should keep studying this stuff.

Personally, it’s my goal to see the need for car traffic decrease a great deal, as part of a global end to capitalist overproduction and a shift in priorities. I’d like to see most land-based transit happening by rail, thus eliminating much of this problem, but we will always have a need to understand how our actions as the force of nature we’ve become affect the ecosystems around us. I feel as though we still have a tendency to view the world in terms of problems and solutions, rather than as something more fluid and dynamic. “Solution” feels like the wrong word, most of the time, because our efforts to improve society are rarely so definitive, and in my way of thinking, it’s always worth trying to do better.

And we’ll never find away around the hypothetical problems with our solutions, until we actually get there. It’s said that a brave person dies but once, while a coward dies a thousand times before their death. As I understand it, that means that the so-called “brave” person accepts that death will come, and tries to live a good life anyway, while the “coward” spends all their imagining how they might die, as part of an obsession with avoiding the inevitable. It feels as though, as a society, we’ve become so obsessed with the ways that life could be worse, that we can barely remember that things could actually get better. I suppose the question is – will we be the ones building forest bridges to save lives, or will we be the deer, so startled by loud noises that we can’t bring ourselves to cross those bridges?

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  1. John Morales says

    Habitat fragmentation and reproductive isolation is definitely a biggie.
    But then, this is the Anthropocene.

    Living here in Oz, I can attest that the road-kill is… quite notable and upsetting.

    (Give the critters a few thousands of years to adjust, maybe… but alas. Highways and roads are not a natural hazard that is handled by their evolutionary history)

  2. Dunc says

    How long until predators start using these choke-points as ambush sites?

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