Wild Neighbors: Dead Skunks and Others: Looking at Roadkill for Science

By Joe Eaton
Thursday September 10, 2009 - 12:16:00 PM

It had to happen. Some enterprising folks at UC Davis have launched the California Roadkill Observation System (CROS), an interactive database whose users can report deceased wildlife they observe while driving. You can either submit your sightings online ( or download and mail in a printed form, indicating species if identifiable, location, type of road, and speed limit.  

Although there are a couple of data points from 2007 and 2008, the observations really began to accumulate in mid-July of this year. They tend to cluster around Davis, with a few from more outlying areas. So far it’s about what you’d expect for summer, heavy on the raccoons, skunks, jackrabbits, and coyotes. Barn owls, which have an unfortunate tendency to fly in front of passing vehicles, are the most common avian victims. Reptiles are sparsely represented by a kingsnake, a rattlesnake and a racer. 

The CROS site also features a map with individual death spots color-coded for large, medium, and small mammals, birds, reptiles, and amphibians. For the truly hard core, there’s a photo gallery. 

I think this is a fine idea. Those so inclined have a new way to entertain themselves on those long road trips, and an opportunity to contribute to science in the bargain. (Just for starters, most of the data on barn owl vehicular collisions comes from Europe.) 

But as a longtime observer, I can anticipate some challenges the system may encounter, beyond the common situation where’s there’s just not enough left for a definitive ID. 

A dead animal out of context may be hard to recognize. Once, while in Little Rock on family business, I passed a defunct roadside beaver half a dozen times before it occurred to me that it was not just an exceptionally ugly dog.  

Then there’s the faux-roadkill problem. The late great Florida herpetologist Archie Carr, who was primarily a turtle man but had a keen eye for snakes, described in his classic The Windward Road how it takes practice to identify a snake species from a moving car “when a layman is still insisting it was a twist of orange peel you passed, or a dead cat.” 

I’ve heard about the tourist driving through Redwood National Park who pulled in at the visitor’s center and, visibly shaken, cornered a ranger. “The highway is full of dead Irish setters!” he blurted out. The ranger had to explain about the strips of redwood bark that fall off log trucks. 

Likewise, a visitor to Hawai’i—I don’t remember which island—was puzzled by the small, furry, flattened creatures she saw all over the back roads. They didn’t quite look like mongooses, but she couldn’t imagine what else they might be. Someone finally apprised her of the local custom of eating mangoes in the car and tossing the pits out the window. 

As data accumulates, it will be interesting to look for seasonal trends. For example, do striped skunk road deaths really increase during the late winter mating season, when the animals are fatally preoccupied?  

And why not take the project national? Is anyone in Texas keeping track of their state mammal? Maverick politician Jim Hightower once proclaimed that there was nothing in the middle of the road but yellow stripes and dead armadillos. These odd but endearing creatures are prone to leap straight up when startled, not the best thing to do with a vehicle bearing down. Texas A & M students have been known to prop them up at the side of the road with Lone Star bottles in their paws. 

The South proper would also be rich in data. In my day, Southerners considered it a point of pride to run over any reptile they could manage to: snakes, of course, but also unoffending turtles. If that has changed, it may only be because they’ve exhausted the supply of reptiles. Carr again, in the Handbook of Turtles: “There exists a curious lot of witless or psychopathic characters who love to run over box turtles on the roads to hear them pop, and there is probably nothing much that can be done about these people except to hope they skid.” 

In all fairness, though, I’ve seen a presumed Californian stop after crushing a Mojave rattlesnake, get out of his car, and shoot the snake, out of concern that it might somehow levitate into the vehicle with his children. 

I don’t keep a list, but there are some critters, like the aforementioned armadillos, badgers, and weasels, that I’ve seen far more often as roadkill than alive. On the other hand, some are seldom if ever observed among the dead. I’m not just thinking about Bigfoot. Have you ever noticed a road-killed crow, raven, or vulture? It must take good reflexes to be a successful highway scavenger.