One species versus 1.8 million others


I'm a student of roadkill. I keep an informal tally of the carcasses I spot on the roadside – what kind, how many and where -- and I note the splatters that accumulate on our car windshield. They're an indication of the diversity and abundance of animal and insect lives along the unnatural transects we call highways.

I know when spring has arrived in my southern Colorado valley as much by the increase in mangled mule deer on the roadside as by the pale green tint that washes this high-desert landscape. The up-tick in deer kill comes when these grazers home in on the smooth brome grass planted on the road margins by the highway department; the brome greens up before the native grasses, providing early and nutritious -- if risky -- grazing.

Similarly, the progress of the Arkansas River caddisfly "hatch" is just as easily read in the numbers of winged adult caddisflies smeared on vehicle windshields, and the quarts of wiper fluid used to remove them, as it is by the number of anglers in the river.

Roadkill may seem like a macabre measure of biological diversity, but it provides interesting, if wrenching, information. It wasn't until I read a recently published study, however, that I realized roadkill also tells us something about the species doing the tallying – and the killing.

In 17 months of roadkill census, researchers at Purdue University found 10,500 carcasses representing more than 65 species of wildlife, most of those from a one-mile stretch of highway traversing a bog. I was so shocked by those numbers that I had to read them twice: 10,500 animals killed on the road in less than two years. And the total carnage may actually have been five times higher. There wasn't enough left of many of the carcasses to count, and  larger animals often manage to make it off the road before they die and are therefore not discovered.

Perhaps the mortality is less shocking when you learn it was mostly frogs: bullfrogs, leopard frogs, and other frog species. The other dead included deer, opossums, raccoons, chimney swifts, garter snakes and salamanders.

Thousands of dead frogs may not seem like much of a concern. But frogs are one of the threads that weave the webs of relationships we call ecosystems, the natural "technology" that keeps our planet green and habitable.

Frog tadpoles chow down on mosquito larvae by the mouthful, keeping populations of the blood-sucking and disease-carrying insects in check without deadly insecticides. Frogs are also a major food source for larger species, from trout and river otters to bald eagles. Massive frog roadkill thus deprives other wildlife of food. Worse still, it attracts other creatures to the road to feed on the dead.

The study's authors suggest that roadkill may be an as-yet-unexamined factor in the worldwide crash of amphibian populations, including the frogs and toads once captured by the jar-full by children throughout North America.

The researchers propose some solutions: Don't route roads through wetlands, provide wildlife with routes over roads or through underpasses, and fence highways to keep wildlife away from the killing zone.

Those are all very nice, but it seems to me that they fail to tackle the underlying problem. And that problem is, of course, overpopulation -- not on the part of the wildlife, but on the part of the species doing the road-killing and the tallying -- Homo sapiens. Us.

There are too many of us. The world's human population has reached nearly 6.7 billion, twice as many people as there were 50 years ago; we're adding another million humans about every four days.

We're the ones building the roads. We're the ones driving the cars. And no, the rise in the price of gas isn't expected to curtail driving enough to really benefit wildlife; it's just likely to push drivers into smaller vehicles. With so many of us, there is simply less room, less food, less habitat, less chance of "them" surviving -- the other 1.8 million known species with whom we share this planet.

Hence the 10,000-plus frogs killed on a one-mile stretch of road. And the wars, the shortages of food, water and fuel, and global climate change. We're the source of the problem. And we're ignoring it. What if we acknowledged that our overpopulation is a serious issue? What if we said it out loud: There are too many of us.

There. The sky did not fall, the world did not end. Let's acknowledge our overpopulation, and do something about it, before it gets worse. The frogs and caddisflies and deer and the ecosystems they participate in will thank us.

Susan Tweit is a contributor to Writers on the Range, a service of High Country News ( She is a writer and naturalist in Salida, Colorado.

Note: the opinions expressed in this column are those of the writer and do not necessarily reflect those of High Country News, its board or staff. If you'd like to share an opinion piece of your own, please write Betsy Marston at

Roy Belmont
Roy Belmont
Sep 29, 2008 02:57 PM
Most everybody's working with the idea of too many of us, except fpr those who believe there can never be too many of us because God's taking care of that.
For the rest it leads directly to triage, priorities, and soft or hard eugenics.
Who should go who should stay?
Volunteers are generally misguided and often the self-sacrificing are the very people you'd want most to keep around.
Those who will valence the question on their own irrefutable right to be the center of whatever form the psecies takes after it trims itself to survival shape are often the very people you'd most want to leave behind, yet they're the ones most likely to game and rig the system.
Pretending to inhabit the center of humanity is a bigtime prominent scam of this age. It functions on all kinds if levels not least that the trimming will happen out on the margins.
The economic version is Social Darwinism yeah? Can't make it in the modern money landscape? Out of the way loser!
So we're all sort of held in check around the question.
Ken Kesey saw it years ago, that the agitation for reduction in population could far too easily lead to the first culls being amongst the gadflies rebels and non-cooperatives. In a sick world that's elevating passive obedient thoughtlessness and crafty selfishness, active smart selfless guys will be marginalized.
He also said it wasn't so much that there were too many of us as there were too many of us living wrong. And if you get the big amoeba upset about being too big it's going to start shedding weight out on the margins. Because it doesn't want to change how it's living.
You see this in miniature with gas. The media's all about people wanting lower prices, but lots of folks out there have figured out that if there weren't so many other cars on the road there'd be more gas to go around. So....
It's a dangerous trough, but being responsible for the elevation of the worst of humankind is a much scarier prospect. This is a probable result of agitating for population reduction right now. Human beings aren't identical replaceable cogs. There are types, varieties, kinds of people. Right now the kinds of people who are protected by material success are not the people I'd nominate to represent us to the rest of the universe, them being generally assholes of one stripe or another.
I hear you, and share the sad shock of seeing so much waste of vital things, essential and even non-essential lives spent unnecessarily.
What's most difficult for me personally is seeing the scum that created this problem lined up and waiting for someone else to start resolving it.

Don Gentry
Don Gentry
Oct 03, 2008 10:12 AM
Roy Belmont, in his objection to those of us who see overpopulation as the single underlying cause of our environmental crises, somehow comes up with the lame idea that if overpopulation is widely recognized, it will result in a survival of the "unfittest". How exactly this would occur is unclear to me. The solution is as obvious as the problem: A uniform reduction of conception rate across all nations and peoples. This could be achieved by voluntary means, supported by tax and other incentives, affecting all people equally. All
that is needed is much wider recognition of the causal relationship of population growth to our many environmental and social problems, and some honesty and fortitude on the part of our politicians. Another big factor that would help, would be for all the naysayers to offer helpful suggestions, or shut up.
Sep 29, 2008 03:46 PM
A very well written article about a subject most want to ignore. Our species is in a breeding frenzy that's resulting in massive global pollution, the scarcity of finite resources, high unemployment and the worth of a human life being diluted. Humankind seems to micro-manage everything but themselves. We munch through everything that gets in our path like 6.7 billion PacMan creatures. Approximately 200 species a day go extinct due in part to our inability to control ourselves. It's just a question of time till we are one of those species and that might be sooner than you think.
Overpopulation kills
Fred Wyman
Fred Wyman
Sep 29, 2008 04:37 PM
The toll that humans take on the rest of the planet has bothered me for quite some time. I am fifty years old and remember an article in "My Weekly Reader" in about third grade (circa 1967) about the population explosion. It troubled me enough then and since that I decided not to procreate. In fact, this is one thing that attracted my wife and I to each other.

Non-procreation is the only solution, and it never fails to baffle me how "politically/environmentally correct" young couples walk around these day with two or three little ones in tow. Recycling ain't gonna fix the problem, people, and neither are dreadlocks. The "my children can/will make a difference" argument is absurd. How many people (including individuals such as Einstein, Bach, Mohammed) have given birth already, and has that made a bit of difference? And who cares if there is no one to take care of you in your old age? Do as the Navajo do, and drag your ass out of the hogan when it is time.

I have also travelled extensively by two wheels, both human powered and motorized. If you ever want to see the carnage that our species leaves with nary a thought on the roadside, take a bicycle tour. You will see incomprehensible numbers that have suffered slaughter at our hands. One stretch of Wyoming highway had about a dozen antelope carcusses per mile. It was heartbreaking.

Last spring I rode across southern Missouri by motorcycle. It was probably the greatest concentration of box turtles that I had ever seen, and most of them were dead on the road or roadside. One had been hit and was squirming in its broken shell. My heart shall be forever rent by the memory.

A decent picture of the average (American) person's view of this debacle is the number of idiots you see wearing those senseless/tasteless "Road kill Cafe" T-shirts. I am not naive enough to believe that humans will stop reproducing, so I have resigned my self to the ever more ugly future that awaits us all.

Just the same, let's all take a moment to picture the paradise that was this planet before homo sapiens showed up.

Thank you for publishing the article and your wonderful journal. Also, thank you for allowing me the opportunity to express my feelings on this important and sensitive subject.

Peace to all. Live your life like this planet belongs to all species.
Cause and effect
Renee DeMartin
Renee DeMartin
Sep 30, 2008 12:27 AM
Rarely, if ever, have I heard anyone involved in a real or probable deer/car accident talk about anything but damage to the car. Road kills haunt me to
no end.
Thanks for a thoughtful article pointing out the REAL cause for these
alarming effects. Humans are far too self centered to acknowledge, let alone
curtail, our over population problem.
Marty Durlin
Marty Durlin
Sep 30, 2008 10:05 AM
A reader reminds us of the book by Barry Lopez, Apologia, based on his 1989 road trip from Oregon to Indiana. Here's an excerpt:

A few miles east of home in the Cascades I slow down and pull over for two raccoons, sprawled still as stones in the road. I carry them to the side and lay them in sun-shot, windblown grass in the barrow pit. In eastern Oregon, along U.S. 20, black-tailed jackrabbits lie like welts of sod – three, four, then a fifth. By the bridge over Jordan Creek, just shy of the Idaho border in the drainage of the Owyhee River, a crumpled adolescent porcupine leers up almost maniacally over its blood-flecked teeth. I carry each one away from the tarmac into a cover of grass or brush out of decency, I think. And worry. Who are these animals, their lights gone out? What journeys have fallen apart here?
F. Felix
F. Felix
Sep 30, 2008 11:33 AM
Here are some folks actually working to solve this problem, rather than just worrying about it.[…]/highway-89-road-ecology.html
John W. Stephens III
John W. Stephens III
Sep 30, 2008 06:03 PM
Those of us who have traveled cross-country by human power (bicycle, tricycle, or in my case, by velomobile) see this up close, smell it when the bodies are hidden, and know, always, that many other users wouldn't mind adding us to that tally.
Concerns about Overpopulation miss a problem
Oct 01, 2008 05:04 PM
The irony of this essay ending in a discussion of overpopulation is that it centers around animals hit by cars and roads-or, as some could be thought of, monuments to cars. Cars are not a good way to measure population size because (due to expanding levels of consumption) there are more and more cars per family (even as the number of children per family may fall).

Car ownership and use is a socially supported habit, money from taxes is often spent on roads. This habit is very strong in the USA and is growing elsewhere, as are consumption levels.

China helps prove the point that there is a difference between population size and what that population does as consumers. In population controlled China the birthrate has fallen remarkably and this, with enough time, could lead to an actual shrinking of the Chinese population rather than just slowing population growth. At the same time the number of cars in China has been growing rapidly. There was once a projection made that the number of cars driven in China will be the same as in the US in 10 years. This projection may or may not pan out but it takes note of the fact that car usage is growing rapidly there. Thus maybe a more direct and more concerning problem is growing consumption rather than population. The latter of which may even shrink in size as the former grows overall.

One of the other things mentioned as an overpopulation related problem is "global climate change" or global warming. But this is inaccurate. Global warming is mostly due to us in the developed world where large families are thought of as unusual but ever more gadgets powered in some way by fossil fuels are not.

In this last regard we should be worried even more for the environment as more of the rest of the world wants to be like us. Throughout its history the USA has had a smaller population than China. Yet only recently has China passed us in the amount of CO2 emitted. This happened after it has both had its population control policy running for years and its people have started buying more cars.
One Species
Oct 02, 2008 09:32 PM
It's refreshing to see this in media. It's unfortunate that the American people are not beaten over the head with this daily. No one wants to touch it.
Thank you for not breeding
Les U. Knight
Les U. Knight
Oct 04, 2008 05:29 PM
Because our breeding is such a mental blind spot, many people immediately think of increasing deaths when we point out that there are too many of us. It might help to add a suggestion or two after stating that something must be done about our population density.

Universal reproductive freedom would greatly reduce the 80 million unwanted conceptions, which result 25 million unwanted births each year. Eliminating baby bounties, encouraging people to think before they breed, and congratulating people who choose to not breed are also ways of improving birth rates without resorting to coercive methods.
Is human overpopulation really an issue?
Oct 07, 2008 07:47 PM
For all you who think the world is over populated, let me give you an idea of how many people there are.

There are 6 billion people on earth. Now that sounds like a lot, but let's put that into perspective.

The state of Rhode Island is 1545 square miles. Let's take that and convert that into sqaure feet, 1545 sq mi = 43,072,128,000 square feet. Divide that by 6 billion and you get just a tad over 7 square feet.
So, the earth's entire human population could stand within an area the size of Rhode Island, standing room only of course. I wonder who we could book to get everyone to attend? Any suggestions? ;P
human overpopulation
Philip Cafaro
Philip Cafaro
Oct 09, 2008 12:38 PM
It is nice to read an environmental essay that acknowledges the role of human overpopulation in biodiversity loss. Those of us who care about nature need to give this issue the priority it deserves.