Fatalities caused by deer are not, as far as we know, caused by deer predation on humans. They are the unfortunate result of more than 2 million people a year plowing into deer with their sedans and SUVs, often on a two-lane road, often at high speed.
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You may wonder: Where and when am I most likely to hit a deer? And how can I avoid it?
To shed light on this dangerous herbivore, we turned, of course, to the data. Specifically, we analyzed more than 1 million animal-vehicle collisions compiled by Calumn Cunningham, Laura Prugh and their colleagues at the University of Washington for a recent paper published in Current Biology. They estimate that deer were involved in more than 90 percent of the collisions, which occurred in 23 states between 1994 and 2021.
With a few exceptions, the data shows that deer are most dangerous in November. In fact, the deer threat peaks before Thanksgiving — usually Nov. 7 to 14 — when you’re about three times more likely to hit a deer than any other time of year.
Seasoned deer hunters can probably guess why driving in November can be Russian roulette on some highways and byways: In most of the country, that’s rutting season. And during the rut, deer focus on reproduction, not self-preservation. Marianne Gauldin of the Alabama Wildlife and Freshwater Fisheries Division compares rutting bucks to teenage boys.
“They were too focused on the opportunity to breed, and therefore lost some of their wits,” Gauldin said. “They are full-tilt looking for something to do, chasing what is being done and chasing what is being done for the opportunity to breed. And they do it with tunnel vision … literally running down the road.”
Do share similar distractions. They are either in estrus — hormonally receptive to sex and looking to breed — or running away hot-and-busy until their cycles catch up.
Collisions occur more often in states with the most white-tailed deer — which experts say tend to have shorter, sharper ruts than western mule deer — and in states with long along busy country roads. Separate insurance claim data from State Farm, widely cited in academic research, shows a driver minding his own business in crooked, crooked roads of West Virginia had a 1 in 35 chance of hitting an animal between June 2021 and June 2022, making the Mountain State easily the most dangerous in terms of deer-car collisions. Montana and Michigan followed. DC drivers, by contrast, had only a 1 in 907 chance of stopping for a buck while driving on Pennsylvania Avenue, or anywhere else.
Fun fact: Deer are responsible for at least 69 percent of animal-related accident claims, according to State Farm. Another 12 percent of claims involved unidentified animals, many of which may have been deer that were tied up before the driver got a good look at them or were damaged beyond recognition in the crash.
The third most dangerous animals on the road are rodents, cited in 5 percent of all animal-related accident claims. However, State Farm spokesman Dave Phillips said many drivers never come into contact with said rodent: Most of those accidents happen when motorists swerve to avoid a suicidal squirrel or moseying over. Marmot.
Those of us more calendar-savvy will note that peak deer-crash season coincides with another big moment in November: the first week of daylight saving time, which begins on the first Sunday of the month. And the University of Washington team found that the two events are unrelated.
To understand why, we need to spelunk deeper into their data, breaking new ground by including the exact location, date and time of all deer disasters. When we glance at a chart of accidents that includes time of day and time of year, one fact strikes us between the headlights: Night, the twilight of every day — especially in November! — is the time of the Götterdeermmerung.
Conveniently for us, University of Washington scholars used the accident’s coordinates and some basic weather math to calculate exactly when the sun will rise or set in each location. It turns out that deer risk peaks about 30 minutes after sunset and remains very high for about half an hour.
Those with experience with deer behavior say drivers should be alert as darkness falls in the fall — especially when walking through deer’s favorite transitional habitats, forest edge ecosystems created by roads and others further developments. But they urge us to take a lesson from the thousands of people who end up in hospitals and body shops every year after trying to avoid a turtle or chipmunk: If you see a deer, don’t swerve.
“Take it as slow as you can, obviously, when it comes to this,” said Karlin Gill of the National Deer Association, a hunting and conservation organization. “But if it’s unavoidable and you hit the deer, don’t try to swerve out of the way. That could cause a worse car wreck, and you could still hit the deer anyway.”
Deer crashes also peak in the morning, about 30 minutes before sunrise, but the number is significantly lower than after sunset. To understand why, we need to dig deeper into both deer and human activity patterns.
Biologist after biologist has told us that deer are crepuscular, meaning they are most active at dawn and dusk. When Texas A&M University wildlife scientist Stephen Webb and his colleagues placed GPS trackers on white-tailed deer in Oklahoma, they found peaks in deer movement at both sunrise and sunset.
“Deer, unlike humans, don’t lie down for eight hours at night and then get up and move around all day,” said Gill, who, as a hunter, closely examines deer behavior. . “They basically go through a cycle where they’ll lie down, lie down, get up, eat, lie down, lie down, get up, eat, and they’ll do it for 24 hours.”
But if deer are equally active at dawn and dusk, why are they more likely to be hit at night? To resolve that one, we need to examine another somewhat crepuscular species: the American commuter. Our commutes also increase in the morning and evening, but we’re more likely to drive at dusk than we are at dawn, and we stay on the roads even after dark and the deer start moving — often facing our headlights.
It’s a matter of visibility. Deer are just as active two hours before dusk as they are two hours after, but we are about 14 times more likely to hit a deer after sunset than before.
And, as Cunningham says, at the top of the whitetail rut, we throw another variable into the stew: We end daylight saving time. All of a sudden, in the deer talk, our 6 pm commute happens an hour later. Millions of drivers find themselves battling lower visibility like sex hormones flooding the local deer population.
“It’s like one of the greatest natural experiments we can do, where humans are imposing these arbitrary and sudden changes on wildlife,” Cunningham told us from his native Tasmania (he’s at the University of Washington as a Fulbright fellow ).
People who live in the far east of a time zone are about 1.35 times more likely to hit a deer than people in the far west, because people in the east are more likely to drive home in the dark. Similarly, people in Northern states, where the days are short and darkness rules the winter, are 1.86 times more likely to hit a deer than their friends in America’s sunny South.
Taking these effects into account, the University of Washington team estimates that the “recession” causes a 16 percent jump in deer kills in the weeks following the relocation. It is possible that the use of permanent daylight saving time will save the lives of over 36,000 deer and 33 people each year.
On the other hand, chronobiologist Eva Winnebeck of the University of Surrey argues that any gains could be offset by the increase in deaths induced by chronic sleepiness that would inevitably occur if our solar-powered circadian rhythms were will be forced to endure endlessly. disconnect between the sun and clocks permanently set to daylight saving time.
Here at the Data Department, we’ve found a strong connection between happiness and the great outdoors. So we’re not partial to any move that gives us more hours of daylight to get out after work and go fishing, running or dominating the competitive wood-chopping circuit, circadian rhythms be damned.
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