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Roadkill Ecology

Several years ago, I woke up to find a possum the size of a small boar in my front yard. It was extremely dead. Unsure about how to handle the matter of disposal, I consulted several friends-all Texans, for what it’s worth-and got an earful of “advice.” One suggested I dump it in my neighbor’s trashcan. Another urged me to douse it in gasoline and set it on fire. A third advocated kicking it to the curb, literally.
One might conclude from these proposals that I have insane friends. But, as it turns out, their suggestions were disturbingly consistent with the solutions practiced by transportation officials across the country. Indeed, the most popular methods of managing roadkill are to dump it in a landfill, incinerate it, or leave it to decompose in roadside ditches. Needless to say, these are far from ideal solutions. But it’s generally what we do.
A decade ago, roadkill-as well as slaughterhouse and butcher waste-didn’t pose such a problem. It was conventionally and conveniently rendered. Putting aside the unsavory fact that it was often rendered into animal feed, the process itself was comparatively efficient and innocuous. But then Mad Cow Disease arrived, leading the USDA to radically tighten rendering regulations. Today, it’s very difficult to locate a rendering plant, much less an affordable one.
All of which turns contemporary carcass removal into something of an open question.? The most promising solution on the horizon appears to be composting. Just as plant matter can be aerobically baked into a valuable soil supplement, so can animal matter. It’s not rocket science, either. “Mortality composting” requires dead animals, “chunky carbonaceous material” (woodchips), a composting site (to build a windrow), and a machine to stir the seething heap every six months or so. Making composting even more attractive is that its environmental bona fides are sound and its experts are at the ready.? Scores of waste management authorities have already developed the processes by which roadkill (mainly deer) can be transformed from highway pulp into soil amendment. The leading authority on the subject, the Cornell Waste Management Institute, has published and distributed detailed guides intended to guide states and municipalities toward effective animal composting programs.
Naturally, there are limitations. Composting windrows require ample open space, and must be located in areas that are well drained and not subject to flooding. Even if adequate amounts of dry woodchips are carefully layered between decaying animals, odor can still be a problem.? It takes a long time for a 150-pound animal carcass to break down-about a year-and the bones are left behind.? There are concerns that a prion disease that deer contract (called Chronic Wasting Disease) would survive composting, which otherwise effectively kills pathogens. The compost heaps can produce mold spores that cause respiratory problems.? In the end, not a lot of compost actually materializes, and, for a variety of reasons, most states will only allow it to serve a non-agricultural public function, such as pushing up roadside daisies.
Minor problems notwithstanding, composting still strikes me as a viable answer to an inevitable problem. Before closing the book on animal composting, though, it’s worth wondering if more direct ecologies remain to be explored. I know that Alaska once fed free moose roadkill to poor people. I’ve heard that there are adventure eaters who will go gourmet with the stuff. A number of resourceful milliners are reported to have manufactured and sold roadkill hats. These ideas seem to be worthy of playing minor roles in the future portfolio of roadkill solutions. But the hidden alternative that really grabs my interest, and the one with a potentially larger role to play, is this one: feeding roadkill to carnivorous zoo animals.
It may sound overly tooth and claw, but consider the context. Zoo nutritionists have been complaining for years that confined animals are-not unlike the humans who observe them-getting fat. The Associated Press reports that there are “love handles, even on bears and gorillas.” Part of the problem is that big game animals are passively slurping pre-processed mush from a bowl rather than actively ripping flesh from bone. Some zoos even spread the packaged food out and lead the animals to it by dragging a bag of zebra poop, if only to get them off their rumps and moving around a bit before chow time. The animals have gotten that lazy.
A carcass tossed into the habitat would address all these problems. The energy required to obtain calories would go up significantly, while the rate at which animals consume food would drop (we all know it’s healthier to eat slowly rather than to gulp our food). Whereas many critics of our overly industrialized food supply lament how unnatural it has become, nothing could be more “all natural” than roadkill.

“Whereas many critics of our overly industrialized food supply lament how unnatural it has become, nothing could be more “all natural” than roadkill.”

And if local roadkill were supplied, zoos could even brag that their animals’ diets were locally sourced. Animal welfare advocates might take assurance in the fact that an animal’s seeking instinct is indulged when it picks clean a carcass. And as for the bones, animals turn them into chew toys and playthings. One can only imagine how carcass feeding would influence zoo attendance.
A few zoos, including the Folsom zoo in California, have already tried the roadkill approach and, aside from a few squeamish patrons, report no negative side effects. And while I’m sure problems would emerge should this solution go mainstream-dangerous pathogens and the expensive requirement of freezing carcasses come to mind-I still think we should give the roadkill-zoo-diet a fair hearing. The United States may very well have more deer today than at the time of European contact and, as for our cars and trucks, we’re now designing them to efficiently dispatch road-crossing beasts.? This is one collision that will only intensify. We should try to get more out of it than a better display of highway wildflowers.