Top

Does Trophy Hunting Spoil The Gene Pool?

January 14, 2009

Yesterday I posted a rebuttal to a Newsweek article that supported the theory that trophy hunting was creating “weak and scrawny” game animals. The Newsweek article used information from a study done on big horn sheep on Ram Mountain in Alberta, Canada, that made the claim by some involved in that study that in 30 years it was trophy hunting that had caused a reduction in body size and horn length and mass. Since that posting, my mailbox has filled up with information.

Trophy hunting, as used in this post and related articles, can be best described as the effort of hunters to select an animal for harvesting that has large antlers/horns in combination with big body mass. The theory is that this type of harvesting selection is creating weaker and smaller species because hunters are culling out the best of the litters to hang on their walls. This simply is not true.

The study conducted on Ram Mountain is long and varied. Much of this controversy began in 2003 when Nature magazine published an article, “Undesirable Evolutionary Consequences of Trophy Hunting”. This link will take you to Nature.com but you have to pay a fee to obtain the whole article.

As I said before, Newsweek referenced the study on Ram Mountain and one of the junior scientists on the project.

Ram Mountain in Alberta, Canada, is home to a population of bighorn sheep, whose most vulnerable individuals are males with thick, curving horns that give them a regal, Princess Leia look. In the course of 30 years of study, biologist Marco Festa-Bianchet of the University of Sherbrooke in Quebec found a roughly 25 percent decline in the size of these horns, and both male and female sheep getting smaller. There’s no mystery on Ram Mountain: male sheep with big horns tend to be larger and produce larger offspring. During the fall rut, or breeding season, these alpha rams mate more than any other males, by winning fights or thwarting other males’ access to their ewes. Their success, however, is contingent upon their surviving the two-month hunting season just before the rut, and in a strange way, they’re competing against their horns. Around the age of 4, their horn size makes them legal game—several years before their reproductive peak. That means smaller-horned males get far more opportunity to mate.

Whether intentional or not, Newsweek didn’t do their homework. Had they, they would have discovered that much controversy followed the Nature article and the Ram Mountain study. It seems that a good chunk of the science community vehemently disagreed with the assessments printed in the Nature piece. Some of those scientists submitted rebuttals to Nature but their work was refused. I have copies of some of the rebuttals.

Dr. Valerius Geist, Professor Emeritus of Environmental Science, The University of Calgary, Canada, was one of the scientists who disagreed with proclamations of the Ram Mountain Study that trophy hunting was producing “undesirable evolutionary consequences”. Dr. Geist submitted the work I’ve provided below to Nature but was denied. (For the complete text of his work, including cited references, click this link to a pdf file.)

TROPHY MALES AS INDIVIDUALS OF LOW FITNESS (DRAFT)

VALERIUS GEIST, Professor emeritus, Faculty of Environmental Design, The University of Calgary, Calgary, Alberta, Canada

While wildlife trophies get a lot of attention in modern times in North America and Europe, such infatuation has a long and instructive history. Already in the Upper Paleolithic, cave painters invariably chose to paint large, complex antlers on male deer and long horns in ibex, bison, and wooly rhinos1. The trophy mania hit its high point in medieval central Europe when huge red deer antlers were used as gifts of state, when hunting records of nobility were recorded in exquisite detail and antlers were venerated objects of display in castles built to house trophy collections2. Such castles have survived into modern times, i.e. the castle of Moritzburg close to Dresden, Germany displays red deer of unequaled size3. These have, naturally, raised the question, “How might such antler growth be duplicated?” Moreover, in the late 19th and early 20th centuries, the vagaries of treatment of wildlife in central Europe led to declines in the trophy quality of antlers which lead to an early “Quality Deer
Management” movement4. This movement reversed the decline within about a quarter century, and generated an intense interest in how to produce huge trophy antlers. We see, currently, in the United States the birth of a similar “Quality Deer Management” movement5,6. Some of the most interesting experimental deer management for trophies was carried out during the Third Reich on the Rominten Heath by Walther Frevert7. There is, consequently, a rich historical background on the biology of “trophy males,” but this is currently poorly known.

The recent study by Coltman et al.8 which demonstrated declines in horn and body size in bighorn rams with hunter selection for large-horned males, confirms the findings from the late 19th and early 20th centuries on European cervids9,10,11. The ongoing removal of males with superior antlers led to a severe shift in sex ratio in favor of females. This imbalance was primarily addressed by the culling males with inferior antlers, while sparing males with good antler growth. Wildlife eugenics, the culling of undesirables, was made popular by Ferdinand von Raesfeld’s “Hege mit der Büchse”12 (husbanding with the rifle) which subsequently was institutionalized in Germany’s 1934 wildlife management legislation13. One thus suspects that, contrary to Coltman et al.’s fears, the declines in horn and body size in bighorn rams are not permanent, but can be reversed by similar means. Even if merely left to themselves, the selection pressures favoring horn size in bighorns14 would return normal horn growth in time. Moreover, the rehabilitation of formerly strip-mined bighorn habitat in Alberta15, as well as the reintroduction of bighorns to former ranges throughout the United States has not merely
increased the wild sheep population of the continent by nearly 50 percent in a quarter century16, but has also resulted in the growth of many rams with record-sized horns17.

In central Europe, management for trophy deer also led to deliberate population reductions, habitat improvements, and the introduction of males with superior antlers from other regions18. The latter, however, was considered a failure19. The interest in improving trophy quality led to research into the nature of body and antler size variations in red deer, with the aim of reproducing antler sizes such has been seen in medieval times 20,21,22,23,24. This illuminated the “biology” of trophy males in clinical detail and led to surprises. One can summarize the findings as follows: Deer varied in body size along a peadomorphhypermorph axis, so that small-bodied deer retained juvenile proportions compared to largebodied deer25,26. Body size was plastic, but slow to shift and it took some five generations for medium-sized deer to reach maximum body size27. This finding, rediscovered three decades later, was labeled the “maternal effect’28,29,30. Continuous access to highly digestible feed rich in protein calcium, and phosphate was a necessary condition for large antler and body size. However, trophy stags were exquisitely sensitive to shortages in food quality31, which indicates that medieval foresters must have been very concerned about the possibilities that their treasured and pampered stags might move off somewhere else. It explains, in part, the brutality with which these foresters treated peasants who disturbed deer. While a high plane of nutrition was a necessary condition for exceptional antler growth, it was not a sufficient condition in itself. Optimal results were achieved by artificially preventing males from rutting33. Males that did not rut had no need to heal the severe rutting wounds suffered by rutting males33, and were thus able to shift their body resources from
repair and re-growth into increased body and antler growth. Moreover, the absence of wounding would lead to the desirable symmetrical antler growth.

However, stags that reached maximum antler development were severely handicapped by their unwieldy antlers in fighting and tended to lose out to normally antlered males. Not infrequently trophy stags locked their complex antlers and died34. Large trophy antlers conveyed no apparent benefit to their bearers, quite the contrary. This suggests that in freeliving populations, male deer with exceptionally large antlers may be non-breeders, and thus individuals of low fitness35. During eight years of field work with habituated mule deer in Waterton National Park, Alberta, Canada, I was fortunate to closely observe three bucks with exceptionally large antlers. All three became “shirkers” during the rutting season. They avoided other deer, bucks especially, and thus failed to court and breed females. They merely fed and rested in seclusion. However, one of these bucks had a surprising history. He had been a normal rutting buck up to three years of age. During a fight with an old buck, he was flung upward and landed on his back in some wind-blown aspen trees. He quit rutting that
year and for two more years. By then, he had grown to a very large body and antler size. The next rutting season he reversed and became a fully engaged, breeding master-buck. He continued as such for three rutting seasons. Hence, “shirking” is potentially reversible. Nevertheless, managing populations for trophy size remains highly questionable, as do the stated concerns of Coltman et al.

In addition to Dr. Geist’s rebuttal efforts, Wayne Heimer, Sheep Biologists for Alaska Department of Fish and Game (1971-1997), Director Foundation for North American Wild Sheep, put together his own rebuttal to the Coltman et al study. He enlisted the expertise of other fish and game experts and scientists for their contributions.

The complete text of “Inferred Negative Effect of “Trophy Hunting” in Alberta: The Great Ram Mountain/Nature Controversy”, can be found by following this link (pdf). Below I have chosen to publish selected pieces of interest.

Wayne Heimer made the following notes and comments:

Compiling Author’s Note and Comment: The wild sheep community is diverse. Specialties within this community range from focus at the molecular level of life increasing in complexity through the cellular level of disease mechanisms and the physiology of life leading to individually adaptive whole-animal behaviors we define as autecology. In animal groups, these individual responses to environment are first defined as “population biology,” and ultimately, synecology. When modern humans interact with mountain sheep synecology, the integration of these diverse disciplines, with the goal of producing human benefits while conserving wild sheep, produces the overarching effort we call “management.”

For optimal management, complete and rational integration of information the diversity represented within the wild sheep community is required. This almost never happens because few “basic researchers” understand the complex nature of management, and few “managers” appreciate the imputed significance of some “basic research.” In the words of actor, Stroether Martin’s prison-warden character in “Cool Hand Luke,” “What we have here is a failure to communicate.” Whether we are “basic researchers” or are working in management at the political level, all of us exhibit the human tendency toward thinking our specialty is the touchstone of successful wild sheep conservation.

The “Great Ram Mountain/NATURE controversy” illustrates this common human weakness compounded by sensationalized communication efforts. Dave Coltman and his co-authors applied molecular genetic analysis to the Ram Mountain (Alta.) data, and published an interpretation which others in the wild sheep community did not find particularly helpful. If the “Nature Science Update” (an electronic digest) hadn’t emphasized Coltman et al’s more extreme suppositions as fact, and if the “NATURE Publishing Group” has not made much of the hunting management- critical interpretations, Coltman et al.’s “Letter to NATURE” would have probably gone largely unnoticed. However NATURE’s radical representation of hunting management criticisms in the tabloid press was interpreted as “anti-hunting,” and was, thus, impossible for other researchers and managers to ignore.

The following collection of essays was produced by way of critique, commentary, and rebuttal. Their “target audiences” vary from the “deeply scientific” to the “popular.” The Frisinas review the contributions hunter-funded conservation has made to wild sheep welfare and cite data which appear to refute the broad “hunting/genetic-harm” claims attributed to Coltman et al.. Rominger points to the unacknowledged variance between the Coltman et al. letter and previously published conclusions where the “et al.” were senior authors. In these unacknowledged papers, density-driven nutritional scarcity was the common rationalization for observed declines in horn and body size on Ram Mountain. Geist discusses the history of “trophy selection” in Europe and suggests alternate (non-genetic) explanations for the changes in horn and body size reported from Ram Mountain. Geist’s essay was submitted to NATURE a rebuttal. It was not accepted for publication. Finally, Heimer and Lee answer Coltman et al.’s allegation that managers have not considered genetic factors in regulation of wild sheep harvest management. They also place the arguments in the unique context of resource management politics in the USA.

If there is any value to recording this event, it is probably simply as a case study where academia and management collided. If there’s a lesson in this history, it may be that “academics” no longer live in a sequestered world. Hence, it may be helpful for everyone in our community to understand what “managers” learned long ago from bitter experience: “Be circumspect in communications with the press because what ‘comes out’ isn’t going to look very much like what you ‘put in.’”

Perhaps more importantly, the wild sheep community, from the loftiest academic to the lowest manager, should realize that scientific data, their interpretation, and the inferences drawn from them have considerably less influence on the decisions that drive management in the “real world” than publicity in the tabloid press. That said, it is perhaps worth noting that, in spite of this spate of creative controversy in the wild sheep community, the world seems to have pretty much forgotten this ever happened…and it’s only been three years. Nevertheless, this “scientific finding” is “out there,” and it would be naïve to presume politically partisan publicists will not resurrect it for use as it suits the anti-hunting agenda. I may be paranoid, but my experience at all levels of involvement in the wild sheep and management communities suggests a high probability it will pop up again…it’s just a matter of when. [WEH]

Michael R. and R. Margaret Frisina, Biologists, Montana Fish Wildlife and Parks, offered their own contribution. Here is a portion of it.

It is obvious that genetics plays a role. If male, you are likely to end up with the hairline of your mother’s father. Still, it is common to overlook how much genetic diversity there is within a specific animal population. Remember the forgotten 50 percent. Ewes contribute half of the genes determining individual sheep characteristics. It is also true that it isn’t only the biggest rams that do the breeding. A recent study of Rocky Mountain bighorn sheep found that although a few larger-horned rams (age 8+ years) had a very high reproductive success, younger rams sired about 50 percent of the lambs. Mating success was not restricted to a few top-ranking rams each year. When all is said and done, the potential for horn size may be set by genes, as are other horn characteristic such as curl tightness and overall shape (probably influenced by both parents), but achieving that potential is limited by the environment occupied by the sheep population. A favorable weather cycle may have contributed to the recent bonanza in huge bighorns harvested, but could not have done so if the genetics for large horns had been previously compromised by harvest management.

Eric Rominger, New Mexico Department of Game and Fish, submits a critique of the letter submitted to and published by Nature. The scathing opening paragraph chastises the authors of the Nature piece as going against their own scientific conclusions.

The conclusions of Coltman et al. (2003) in their recently published NATURE article contradict nearly 20 years of analyses published primarily by two co-authors of the manuscript (i.e. Jorgenson and Festa-Bianchet). After asserting, in a series of refereed scientific publications (e.g. Jorgenson et al. 1984, 1993, 1998, Festa-Bianchet et al. 1997, LeBlanc et al. 2001), that reductions in body mass and horn size of rams from the Ram Mountain population were the result of density-related decreases in forage availability, these authors have either chosen to ignore or recant their previous work. They have not acknowledged their apparent changes in perspective. Apparently these authors now conclude that, in fact, trophy hunting has induced the declines observed in ram body mass and horn size on Ram Mountain. In confusing contrast, a paper published in BEHAVIORAL ECOLOGY shortly after their NATURE article reports that 77.2% and 86.8% of the variance in body mass and annuli base circumference were explainable by a liner mixed effects model describing the effects of resource availability and age (Festa-Bianchet et al. 2004).

Wayne Heimer and Raymond M. Lee, coauthored their own work, “Undesirable Consequences of Unqualified Speculation on the Negative Effects of Trophy Ram Hunting”. Raymond M. Lee is President/CEO, Foundation for North American Wild Sheep.

Status-enhancing, but highly speculative, publications such as Coltman et al.1, may compromise wild sheep conservation. Such research communications encourage emotionally driven anti-hunters to contravene biologically sound management programs, particularly in the United States. Coltman et al.’s1 letter grossly exaggerated hazards to wild sheep populations resulting from managed human harvests. It’s secondary references to “sport harvesting” as “one of the most pervasive and potentially intrusive human activities that affect game mammal populations globally2, and the statement that “little attention has been paid to the potential evolutionary consequences, and hence the sustainability of harvest regimes3,4” are incorrect and damagingly expansive. The letter reported larger-horned, larger-bodied rams sire more lambs than smaller individuals; and made much of the fact that human harvesters prefer the largest rams available. These findings are not new. Reproductive success was quantitatively linked to dominance three decades ago5. Modern “sport harvesting” management of wild mountain sheep has typically limited harvest to 3-10% of available rams for more than 40 years. In Alaska, the most prolific and harvest-friendly wild sheep jurisdiction in the world, harvest strategies have been specifically designed to foster social order among rams for almost 20 years6. Alternate rutting strategies among thinhorn sheep resulting from differing ram mortality levels were identified and factored into sheep harvest management in Alaska beginning in 19847,8. Coleman et al’s failure to acknowledge these facts was compounded by sensationalized reporting of these non-revolutionary findings by the “NATURE Science Update” and the NATURE Publishing Group9,10. Similar under-researched and over-sensationalized “scientific communications” are often used by animal rights groups and “anti-hunters” to orchestrate politically saleable, but biologically counter-productive ‘corrections’ in management programs through so called “citizen’s initiatives” in the United States. These actions serve neither science, conservation, nor the managed species will in the longer run.

These are only selected parts of the completed piece put together by Heimer. I apologize for the length of this writing but I feel that it is important, not only to educate interested readers but to clearly and scientifically refute articles such as has been published in Newsweek magazine. It is this kind of media that not only damages the decades of work done to save and conserve our game species, through time and fees from hunters, but it also puts the very species we work to protect in danger.

As I concluded at the end of yesterday’s post, I am left only to conclude that the author’s objective in penning the Newsweek article is strictly political.

For more information on wild sheep and goats, visit the website of the Northern Wild Sheep and Goat Council.

I would also like to thank, Dr. Charles Kay, Dr. Valerius Geist and Wayne Heiman for taking the time to respond to my requests and unselfishly giving of their time and expertise. It is because of people like these that we can, at least for now, be assured the hunting and wildlife community has the right people working for us all.

Tom Remington

Comments

One Response to “Does Trophy Hunting Spoil The Gene Pool?”

  1. Biologist123 on January 10th, 2011 8:20 am

    The scientific articles that you have posted as “rebuttals” do not support your argument as you so vehemently claim.

    Geist supports the idea that selectively culling animals with larger antlers/horns (such as deer in the majority of this article, but also with the rams mentioned) results in decreased body mass and horn size, but merely disagrees that these changes are permanent, which any logically thinking person could conclude. (Support provided by the Frisina’s.)

    In any case, this effect has been occurring for thousands of years – look at the selective breeding of dairy/beef cattle for those that produce the largest quantities of milk, or those with the most muscle. Or are these effects made up too?

    Recording the horn sizes and body weights of rams over 30 years is a good way to see how the environment is impacting these species, and obviously killing the largest of the species before their breeding season will increase selection pressures favoring the smaller of the species due to there being less genes for these large traits in the gene pool. Whilst these changes are most certainly not permanent, the reversal would require the elimination of hunting from the area for a period of decades.

Got something to say?






Bottom