According to the popular logic, the wolves preyed on elk, keeping the grazers’ populations in check, which allowed dwindling aspen populations, and the beavers that fed on them, to rebound. This logic was affirmed in 2007 when Scott Creel, an ecologist at Montana State University, published a study suggesting that the presence of wolves stressed the elk, leading to poor female health and fewer pregnancies.
But as the wolves proliferated, they came in direct conflict with the true top predator in the area — humans. The canines lurked near homes and preyed on livestock and occasionally pets, provoking growing resentment from residents. Simmering hostilities eventually boiled over: Hunters wanted to get rid of the wolves, while conservationists still sang the wolves’ ecological praises. The strong opinions on both sides were fueled by conflicting data, so the battle raged on, in and out of the courtroom.
Creel’s paper was seen as damning evidence against wolves, but his results were based on indirect observations. To effectively manage wolf and elk populations, the U.S. Fish and Wildlife Service and the Wyoming Game and Fish Department needed more, reliable data. The same year that Creel published his study, Middleton, then a Ph.D. student at the University of Wyoming, was put in charge of an ambitious research project to investigate more directly the effects of wolves on the elk population.
Over the next three years, he fitted 90 female elk and 15 wolves with GPS collars, which recorded their coordinates every three hours. From these data, a detailed map of long-term elk and wolf movements emerged. Middleton’s crew also counted the number of calves that survived each summer and recaptured the collared female elk twice a year for health checkups. He determined that the pregnancy rate among elk in the migrating herd was 19 percent lower than non-migrating herds nearby, and that from 1989 to 2009, the number of calves surviving to adulthood had declined a staggering 74 percent.
To confirm these numbers on the ground, Middleton spent months in the wild observing elk — a part of the job he came to loathe. Elk, he soon learned, don’t put on much of a show. “They eat. They lie down and ruminate. They walk around. And sometimes, they bite each other. It’s painfully boring,” he says, and he means that literally. “It’s freezing cold, and you’re usually hiking up some steep, snowbound slope, post-holing your way to the top, to some high observation point, getting all hot and sweaty and then standing still for hours and cooling back down to the point where you’re nearly hypothermic.”
Most conservation biologists and locals assumed Middleton’s research would provide the evidence state and federal agencies needed to support controlling the problematic wolf populations in Wyoming. But Middleton’s observations and GPS data showed that elk rarely encountered wolves. And when they did, the elk didn’t run away or even stop chewing unless the wolves came within about half a mile. Most importantly, there was no correlation between the rate of wolf encounters and the decline of either elk pregnancy rates or their levels of body fat, which are crucial for surviving the cold winter.