Midnight Wolverine

After coming home from a long day on the job, most people would dread getting a call from the office saying they needed to get back to work immediately, and then for another 6 hours or more. This couldn’t be farther from the truth for us, the Wildlife Conservation Society’s Arctic Beringia wolverine research crew. On March 30th, that call was a satellite-transmitted message telling us that one of our wolverine live traps had closed. What was inside was unknown; what we did know is that we were excited to find out, that night was quickly encroaching, and that the temperatures were already below zero Fahrenheit.


The moment a pin is pulled from the satellite communicator as the trap closes, prompting us to drop what we are doing and head to the trap. Photo credit: Matt Kynoch.

Despite the timing and dropping temperatures, it was a moment we had been eagerly anticipating for weeks. We’d seen tracks and pictures from remote cameras of an elusive wolverine making somewhat liberal use of the area, but this animal had consistently avoided our traps. After a full day’s work covering around 80 miles on rough and non-existent trails, following wolverine tracks and hauling gear, we ate a quick dinner and excitedly regrouped. Based on tracks we’d seen in the area, the anticipation of finding a wolverine in our trap was high – but we were cognizant to the fact it could be a fox.

Our snow machines made it the 8 miles to the trap in less than an hour, though the journey to a triggered trap can feel like an eternity when you’re bubbling with the anticipation of coming face to face with a new wolverine in a 30”x 5’ wooden box. A quick peek inside the trap revealed a small, surprisingly docile wolverine, more concerned with slobbering over the sweet-smelling carcass we had used as bait, than reacting to our flashlights and prying eyes. Others we’d caught earlier in the season would make their displeasure at capture much better known as they paced and growled in the dust and splinters of attempts to chew their way out of the boxes.


The wolverine trap (left) and Arctic Oven tent where the wolverine is processed in relative warmth to the sub zero temperatures outside. The northern lights in full spate. Photo: Matt Kynoch.

On this night, we had captured a young male, on the small side for male morphology. After a carefully placed anesthetic injection in the rump from a jab stick, essentially a syringe on the end of a pole, the animal could be moved inside our bright yellow Arctic Oven tent. These tents are an arctic camper’s dream, big enough to stand in, and also able to accommodate a fire due to vents in the roof – in our case we heated it with a roaring propane heater. We laid the sedated wolverine on blankets and hot water bottles before measuring him, attaching a satellite collar and an ear tag, and applying antibiotic ointment to a small wound above his left rear leg that looked to have been sustained a couple of days earlier. None of our other captures this year had any sort of injury. There was no indication as what may have been the cause, but it was nevertheless a reminder of the dangers of being a predator in this unforgiving environment. Within an hour our work was done and the small male was placed back in the trap in a blanket, to recover from the immobilization drugs.


Wolverine and researcher come face to face for the first time. Photo credit: Matt Kynoch.

Most of our days are filled with riding snow machines for long hours, searching for tracks and sign of new wolverines in the foothills of the Brooks Range, or in the many river floodplains that transect the tundra. During these times, with earplugs in, our heads enveloped in full-face helmets, and wrapped up like the Pillsbury Dough Boy in warm bibs and jackets, it’s easy to feel removed from the environment. However, in the couple of hours it took for this young male to be fully recuperated for release, the five of us were treated to more than the gift of this new wolverine. It started with just a few wisps of aurora across a night sky lit only be a thumbnail of a moon and stars. But the aurora grew in intensity to a truly breathtaking display over our temporary wolverine camp – a swirling morass of color that covered the sky at its zenith. At times, the surging colors looked to be within arm’s reach, dancing just above our heads. It was as if the light show over the tundra was just for us and this wolverine. Once released, he loped away in that characteristic 3×4 gait of wolverines, passing out of range of our headlamps, and leaving tracks for us again – but now also breadcrumbs of locations, relayed to us by distant satellites.


Lead WCS wolverine researcher Tom Glass checking the wolverine prior to handling. Photo credit: Tom Glass.

In the next 24 hours, the animal traveled over 20 miles south into the Brooks Range. He scaled 6,500 foot peaks and precipitous ridges, demonstrating a typical wolverine disregard for topography. The data he provides us will not only paint a picture for male home range movements and activities during the breeding season on Alaska’s North Slope, but also possibly how he relates to other animals that we are monitoring in the area.


The northern lights tinged with color on our trail home. Photo credit: Matt Kynoch.






Examining wolverine snow holes in light of a changing climate

The alpenglow cast long shadows as we approached the summit. Here in the foothills of the Brooks Range, on top of an isolated peak, we were looking for wolverines. More specifically, we were looking for wolverine snow-holes – places where they had stopped, dug a tunnel into the snow, and rested, sometimes for hours or days.

Wolverine crew.jpg

The WCS wolverine field crew out tracking wolverines, March 2017. Photo credit Matt Kynoch.

The focus of our project is understanding how wolverines use these holes, and what snow characteristics are important to them. In a warming Arctic, this question takes on a heightened significance: will earlier spring snowmelt affect the animal’s ability to raise kits and find appropriate shelter?


A young female wolverine stands outside the trap that will eventually temporarily trap her. Photo is taken by a Reconyx remote camera.

The 2017 field season is off to a promising start. The young female pictured above is the fourth of our captures so far. On her first visit to the trap, before it was set, she played with the caribou leg behind her for hours, rolling underneath it, tugging, fighting to get it free. Once we did set it, it didn’t take long for her to be tempted in.

On account of a rather round, portly build, we’ve started calling her Po. Her processing went smoothly, and she was up and running again within a few hours. That was three days ago. Since then, she’s traveled 20 km, summited a mountain, and led us to seven different snow-holes. Other animals that we’ve captured appear to make and use snow-holes at a similar, or slightly lower rate – around one per day. Some of the animals are re-using holes, returning to them after a week’s absence, including holes originally created by other wolverines!


Example of a wolverine snow hole. Wolverines use these holes as resting sites, to raise kits, and possibly to cache food. Photo credit Tom Glass.

Pictured above is where Po took a 10-hour nap shortly after she left the trap. She’s now out on the tundra, wearing a GPS collar that includes an accelerometer and light-logger, instruments that will help us better understand the energetics of her movements, and how she and other wolverines use snow for structure here on the North Slope. Only through such detailed investigation can we fully appreciate what these animals need to thrive in this expansive landscape, and what threats they face in a changing world.

F6 release (2 of 2).jpg

“Po” the female wolverine after being fitted with a satellite collar and released on the North Slope of Alaska. Photo credit Matt Kynoch.

Remnants of Winter

A month ago, on the 29th of May, I spent a day collecting the thirteen motion-activated cameras that we deployed on wolverine snow-holes this spring, not knowing anything about the photos taken in our absence. Across the tundra, most of the snow was gone, patches remaining only in drainages and cut banks where it had drifted during the winter.


Helen Chmura uses a radio tracker near the Colville River to locate collared wolverines. Photo Tom Glass.

In keeping with what we know about wolverines, most (though not all) of the sites where they had created holes still had some snow, where we found evidence of how they had used the area. It is the relationship between wolverines and spring snow that drives many of our research questions.


A snow filled drainage as we approached the study area. Photo Tom Glass.

Upon reviewing the photos from the cameras, we discovered that five of the holes were associated with kits. At three of these, we found substantial latrines – piles of scat about a foot in diameter and several inches tall. We collected these as evidence, hoping to more fully examine their diet, and possibly to obtain a genetic sample from the kits, which would allow us to follow family relationships if we catch them again later as adults.

At many of these sites, we were also able to see the remains of the tunnels that the wolverines had excavated and used. These were extensive, sometimes stretching as much as forty feet from one end to the other. At one site we found beds, where the wolverine had apparently brought moss into the den for insulation and comfort, which were now suspended on pedestals, all other snow having melted around them.   Many sites also contained food remains, like caribou hooves, bones, and hair.


A latrine inside a natal den (left side of frame). The sticks and debris leading away to the right likely mark the location of a tunnel. There was also a partially consumed caribou leg in this latrine. Photo Tom Glass.


A moss bed, formerly inside a wolverine snow structure before the snow melt.Photo Tom Glass.


Looking down a partially collapsed tunnel. Scat and bones litter then length of this section. Photo Tom Glass.

Upon approaching one site, an adult wolverine fled into a remnant tunnel in the snow. One of our primary questions is when and why wolverines leave the snow structures, so it was fascinating to observe this individual still using the site. After some deliberation, we decided to approach cautiously to retrieve the camera. When we arrived, we found two kits – both dead – on the snow near the entrance of the tunnel. A necropsy found no obvious wounds to either (though one was partially consumed), and the intact kit was severely underweight for its age. From this, our best guess is that the mother was killed (either by a predator, like a wolf, or by hunters), and the kits were left to fend for themselves. This leaves the question of the adult wolverine we observed at the hole – possibly the father, or simply another interested party. Unfortunately, our camera did not stay standing long enough to provide any evidence.


The adult wolverine fleeing into a hole as we approached. Photo Tom Glass.

At one hole, a natal den, we captured nearly 4,000 pictures of the mother, kits, and presumed father coming and going from the area. Among these, there is a series which depicts the mother nursing the three kits, at the entrance of the den, while the male observes from a distance. In another set, the mother arrives at the den and drags in a caribou leg. In others, the kits tumble playfully around the entrance. These are fascinating windows into the lives of these creatures, about whom we know so little. In most cases, snippets like these create more questions than they answer, providing the impetus to get back out there, don the parka, and keep searching.

Written by Tom Glass, WCS research technician. June 2016.

First Attempts: Tracking Wolverines on Alaska’s North Slope

On April 29th, Ross Dorendorf and I swung our legs over our snow machines and gave each other a thumbs up; it was time to head home. We had just completed the initial season of the first ground-based collaring effort for wolverines on Alaska’s North Slope in 35 years – the second ever – and were pleased to call it a success. For fifty days we ran four traps, complemented by ten bait stations, covering approximately 500 square miles of tundra near the oil camp of Umiat. It was the first effort to shed light on how wolverines use deep snow as a structural feature of their habitat, and it was very much a pilot season, one of several to come. In a landscape where woody plants are scarce, we had no way to know what the wolverines would think of our wooden traps constructed of commercial 4x4s, but we hoped that the animal’s characteristic curiosity and namesake gluttony would overcome any reservations it had about jumping in.


Tom Glass prepares the snow machines for daily checks of the wolverine traps. Photo R. Dorendorf

Though slow to start, we ultimately captured four different wolverines (possibly five – one got away before we reached the trap), and collared three. With the generous aid of the Alaska Department of Fish & Game, we were able to deploy two more collars, for a total of five wolverines now out on the tundra, transmitting data. Two are lactating females.


Tom Glass holds an adult male wolverine after removal from the box trap (in background). Photo R. Dorendorf

But this figure is only a part of what allows us to claim success. In our seven weeks there, we also collected 88 scats for diet analysis and genetic information, followed over 40 miles of wolverine tracks to understand where the animals traveled, remotely observed what may be the first GPS documentation of a wolverine traveling on sea ice, and deployed 13 motion activated cameras on snow-holes created by wolverines.


Following the wolverine on Alaska’s North Slope. Photo R. Dorendorf.

This last number is worth expounding. With the aid of aerial observers Tina Laird, Mark Keech, Pat Valkenburg, and Audrey Magoun, we located and investigated around twenty holes dug by wolverines in the snow. On the surface, these holes are unassuming. Some are accompanied by scat or food remains (often caribou or moose bones), while others are meticulously clean. Some have dozens of tracks coming and going, while others appear to have only been used once. At some, the opening is small – often a mere 7-8”—while at others a wide entrance leads into a large (~2′ diameter) cavern. Some are created in relatively shallow snow, while others are dug into meters-deep drifts, often on the lee of cut banks or lake shores.


Photo of a female wolverine captured by remote camera near a den site on Alaska’s North Slope.

We are intensely curious about these holes. Around the world, wolverine distribution is strongly correlated with snow that persists late into spring, but no one fully understands why. In the Lower 48, where increasingly warm winters mean less late-season snow, this relationship may put the species in peril. On the tundra, wolverines seeking some sort of structure (for protection from predators, to raise their kits, to store food, or for any number of other reasons) have little choice but to dig holes in the snow. Unlike wolverines in most other places, these animals live above treeline, and cannot hide under boulders (for the most part – there are few here), root wads, or downed timber. They must entirely create their own structure.

We think that snow on the North Slope may play a crucial role in the life of a wolverine, and that coming to understand this role may unlock if and how the changing climate will impact wolverines in the Lower 48, and around the world. In three weeks, I will return to the study area to collect our thirteen cameras, which we hope hold a first glimpse into this mystery.

In the meantime, our aerial observers are back at it, investigating whether GPS-clusters transmitted by our collared animals might be dens or other snow structures. Very little is known about how wolverines use snow for structure, and we hope to change that.


Written by Tom Glass, WCS Wolverine Research Technician. April 2016.

Arctic Wolverine Surveys

In April of this year two Supercubs glided to a landing in Umiat, a lonely outpost on the North Slope of Alaska. It was decidedly not spring this far north as evidenced by the frozen Colville River and the snow-covered tundra all around. From one of the planes emerged Audrey Magoun, a pioneering wolverine biologist and her husband, pilot/wildlife biologist Pat Valkenburg. From the other airplane, Mark Keech, also a pilot/wildlife biologist, and his wife, geologist Tina Laird, also unfolded themselves from the cramped space they had been occupying for 6 hours and stretched their legs. They’d been flying these small airplanes back and forth across the top of the continent for weeks, at least on those days when they weren’t grounded by low-lying fog banks and blizzards. They had stopped at Umiat to re-fuel the airplanes for another pass across vast white expanses where they hoped to find tracks of wolverines and other species inhabiting the Arctic Slope, an area stretching from the Brooks Range to the Arctic Ocean. Sponsored by the Wildlife Conservation Society’s Arctic Beringia program, they were conducting the most comprehensive survey of wolverines on the Arctic Slope that has ever been done, in order to make a baseline map of wolverine distribution at its current population level. On a map of the Arctic Slope of Alaska they overlaid a grid of hexagons across a 62,000 square-mile study area and flew from the center of one hexagon to another recording wolverines and their tracks as well as signs of other wildlife, including wolves, caribou, muskox, and moose.

IMG_0538_cropped_den flyover_2

A wolverine den can be seen off of the right wing of the airplane shadow. Keen eyesight and attention to detail are necessary to conduct aerial tracking surveys.

Because they are superbly adapted to snowy environments, wolverines in the lower 48 states are thought to be vulnerable to climate change. In Canada they are considered a species of special concern because of increasing industrial activity and human access to its remote habitats via new roads and more snowmobiles. Very little is known about the potential effect of climate change and human developments on wolverines in Alaska, but their dependence on snowdrifts for sheltering their young and caching food in the tundra habitats of the Arctic Slope suggests that climate change could be a factor in the future of wolverines in the region.

A wolverine on the North Slope of Alaska as seen from the Super Cub during aerial tracking surveys in April 2015.

A wolverine on the North Slope of Alaska as seen from the Super Cub during aerial tracking surveys in April 2015.

Wolverines are solitary animals, members of the weasel family, with relatively large ranges, with some male wolverines occupying 150 square miles or more. One of the iconic species found in arctic Alaska, the wolverines is virtually proof of a true northern wilderness area. As Audrey says, “if an area doesn’t have wolverines, I don’t feel like I’m in the northern wilderness.” The airplanes used the long days of the arctic spring to fly nearly 14,000 miles, recording tracks, dens, and the occasional animal. Audrey and the crew spent time in the remote villages of Umiat, Barrow, and Atqasuk waiting for blizzards to pass and talking to locals who report that this year is a particularly good year for wolverines. Anecdotal information like that tells us basic information, that numbers of wolverines fluctuate between years, though we don’t yet know what affects wolverine numbers and distribution. Local trappers capture wolverines to use for fur ruffs and trim on their winter parkas and to sell to others in the villages who do not trap. At this time, there is little information on the number of wolverines trapped on the Arctic Slope or whether trapping is influencing distribution or numbers of wolverines in the study area. The Wildlife Conservation Society has recently secured funding from the Murdock Foundation to study the relationship of wolverines to snow, particularly snowdrifts that linger into spring and summer, and to conduct genetic and toxicological studies on Arctic Slope wolverines. This new work will build on our understanding of wolverines in the lower 48 States, Alaska, and Canada and particularly on Audrey’s work on wolverines in northwest Alaska in the 1980s. Understanding such factors as importance of snowdrifts, presence of other species, trapping pressure, and the health, size, and structure of the wolverine population will help guide future development location and practices and help this species thrive in the changing arctic environment.

WCS wolverine surveys

Flight lines flown during wolverine surveys. The intensity of color indicates number of times flown.