Happy Wolverines’ Birthday

I wanted to quickly post two thoughts: first, belatedly, Happy Valentine’s Day. This is actually an important day for wolverines all over the world, since it marks the approximate date of birth for every wild wolverine on the planet. As I write, female wolverines from the US to Canada to Russia to Mongolia to Scandinavia are burrowing into their snow dens and giving birth. If our female wolverine F3 is pregnant this year, that’s what she is most likely doing too.

At some point soon we will try to determine whether or not she’s localized by sending a telemetry flight on three successive days.  If the flight locates her in the same area over those three days, she is most likely in a den with kits. I’m also curious as to what M57, her mate, is up to, and whether he is also in proximity to the den (if there is one…), since father wolverines play some role in protecting and raising their offspring. The precise parameters of this role are still up for debate, so if F3 is denning, it will be interesting to follow M57 as well. (Several days after we caught F3 last month, M57 also went into the trap; we didn’t have a collar ready and had to let him go, but he and F3 were at least relatively close to each other as of a few weeks ago.)

I waited to post this until today, since February 15th marks the close of Montana’s wolverine trapping season. Three wolverines in total were killed in the state this year, at least one of them a female. No wolverines were reported killed in region 3, where F3 and M57 live. I’ve had several comments over the past few weeks about trapping, and this is something I intend to write about soon, in connection with the broader issue of how we manage social conflicts around wildlife conservation. For now, I’m incredibly relieved that F3 and M57 made it through another year, and, although I am not opposed to the idea of hunting, and have a lot of respect for ethical hunters both here in the US and in Mongolia, I am also sorry for the loss of those three animals, for the sake of the overall wolverine population. I wish that Montana was crawling with so many wolverines that every trapper could take one and it wouldn’t even make a difference to the population at all. Unfortunately the scientific evidence points increasingly towards the fact that this is not the case.

What to Expect When Your Wolverine Is Expecting

Last Monday the Absaroka-Beartooth Project’s female wolverine F3 went into one of the project’s live traps in Montana. Jason Wilmot, Jeff Copeland, and several other participants drove up to re-instrument her. It was an early-season capture; usually wolverines hit the traps hard starting in March. Not for nothing are wolverines referred to as gluttons, so it’s hardly surprising that a gulo would grab an extra bite at any time of year, but a possible spur to F3’s early trap raiding became evident when the crew saw that her teats were enlarged; F3 is probably pregnant!

We captured F3 late last March and had to search through the fur of her belly to even find her teats; disappointingly, they were nearly non-existent, meaning that she was probably not pregnant and had not given birth last year. Understanding reproduction is the crux of the question of a species’ status, and with wolverines, data on reproduction are notoriously hard to obtain. Beyond the statistics, of course, a birth in any rare species is cause for celebration. F3 is about five years old, and although female wolverines reach sexual maturity at around two, most don’t reproduce until they’re three or four. We had high hopes for F3 when M57 moved into her territory two summers ago, but last year, although they had been in each other’s company during the breeding season, no kits appeared.

This didn’t mean that they hadn’t mated; wolverines, like other mustelids, bears, and several other mammal families, have a system of resource-governed pregnancy known as embroynic diapause or delayed implantation. A wolverine may mate and the eggs may be fertilized, but they don’t implant and develop until months later. If resources are too scarce and the female isn’t in good enough condition to bear and nurse young, the embryos dissolve without implanting.

Presumably in wolverines this reproductive strategy helps deal with the fact that the animals are sparsely distributed over the landscape; who knows when you’re going to meet again, so you might as well make every effort to insure the future of the species when you do run across each other. Delayed implantation probably also helps female wolverines cope with the sparsity of resources in their severe habitats; reproduction is hugely energetically expensive for any animal, and if the environment isn’t able to support a female through the intense periods of pregnancy and nursing, it makes no sense to put the energy into giving birth to young that will probably starve. Delayed implantation is a strategy that allows wolverines to fine-tune births to the best possible conditions for reproductive success.

Once implanted, gestation is quick, between a month and six weeks. The kits are born around Valentine’s Day, usually twins but sometimes up to four, deep in a snow den that the mother excavates. They are tiny, pure white, and helpless. A man who has kept captive wolverines for many years and has successfully facilitated a number of births says, as related in Doug Chadwick’s The Wolverine Way, that the kits are born with some sort of waxy substance on their fur and that this substance smells so horrible that it’s hard to get close to a newborn wolverine without getting nauseous. Presumably this, along with 10-foot-deep snow dens, is a defense against predation while the kits are vulnerable.

Female wolverines nurse their young for about three months, moving them among a series of dens before they emerge around mid-May. By this time, they are unrecognizable as the tiny white creatures born in February; they already have full gulo coloring and are close to adult size. They are not quite independent yet, though, and they stay with their mom through the fall. For the next year, still not quite ready to be on their own, they roam their parents’ territories and sometimes rejoin each other, their mother, or their father to play, to learn how to find particularly good carrion, to get some tips on hunting ground squirrels, or simply to pursue the mysteries of wolverine life in company. At the onset of full adulthood, around age two, they set off to carve out their own territories – if they survive. The Glacier National Park Wolverine Project recorded rates of juvenile mortality at around 50%; the world is a perilous place for a young wolverine. And then, even if a young wolverine makes it to its own new territory, it might still face what can be referred to as the M56 Dilemma; travel 500 miles across all kinds of obstacles, only to discover that the new territory is a little too vacant, and that there are no mates to be found.

Add to all these contingencies the fact that a female wolverine at peak condition and with all the resources she needs generally only produces kits every other year, and the survival of the species at all, let alone among widely separated mountain ranges, begins to seem miraculous.

The title of the blog post is something of an inside joke, because while I’m sure that giving birth provides its own sense of gratification to the female wolverine involved, wolverine researchers also have a distinct experience around wolverine pregnancy, and that experience seems primarily to be one of extreme uncertainty and a total suspension of expectations. The chain of uncertainty goes something like this:

Great! We have a male and a female wolverine hanging out together! Will they mate?

Okay, so if they mated, will she become pregnant, or will she resorb the fertilized eggs?

Wow, it looks like she might be pregnant! Will she manage to successfully den? Will she even give birth, since wolverines known to be pregnant in Glacier later appeared not to have had kits?

If she successfully dens and gives birth, will we be able to tell that she’s denning?

If she is denning, and even if we know she’s denning, will she be able to successfully nurse her kits until May?

If the kits live, it’s imperative to instrument them, because this will provide absolutely critical data on dispersal – but can we find the den?

If we find the den, do we have anyone seriously hardcore enough to get to it?

If we find the den and instrument the kits, will we be able to successfully track them, or will they disappear from the airwaves like so many other juveniles wolverines have done before?

Even if we have the human and technical capacity to do all of this, do we actually have the funding to pay for collars, implants, flights, and salaries?

These questions, no doubt, result in a number of sleepless nights for the expectant researchers; since the big news came in last week, I’ve already chalked up two. Wolverines are tricksters, and F3 in particular has had an uncanny knack for raising our hopes and then smacking them right back down. The uncertainty, though, is tempered by moments of euphoria, because if she is pregnant, and if she gives birth, and if we can instrument and track the kits, it’s a huge set of information on how wolverines function as a meta-population in the Rockies. Huge. And it’s worth all the uncertainty and the sleepless nights and the frozen fingers and toes and the near-death experiences if it can help in some way to tell us how to keep the species on the landscape over the long term.

So, F3 and M57, congratulations on your big news….if your big news is really the big news that we think it is. We will be eagerly waiting to find out.

Two bears and a collar

On Sunday afternoon, a growl yanked my attention from the undergrowth, at which I’d been peering intently; a few dozen yards from where I stood in a cluster of pine trees that opened onto an expanse of meadow high in the Absarokas, two bears were locked in what appeared to be combat, standing on hind legs, batting each other. One was pitch black, the other cinnamon. Their trajectory as they circled and growled and wrestled was straight towards me, although they hadn’t seen me yet. I beat a hasty, silent retreat up a nearby slope, slipping between blackened trunks of a burn, trying to keep one eye on the bears and the other on my footing. The telemetry antenna and receiver that I was carrying were awkward, and more so as I fumbled to make sure my bear spray was within reach. At the top of the slope, sweating and covered in ash and charcoal from the burn, I slumped against a charred tree trunk and began to take the antenna apart.

Back in March, en route to one of the research traps in Montana, Jason pulled over on the side of the road to test the GPS collar that we were about to put on M57. Jason tuned the telemetry receiver and then removed the magnet – which keeps the collar turned off until we’re ready to deploy it – and the steady pulse of the radio signal filled the cab of the truck. We drove on, and a few hours later, M57 took off into the trees, carrying the collar. It was scheduled to record locations via satellite every two hours. This allows a more refined understanding of how wolverines move over the landscape than radio telemetry locations, which are sporadic at best.

The collars that we’d put on M57 and F3 were scheduled to release in October, but by June 1st, both had managed to escape their collars; wolverines are notorious for their ability to do this. M57’s was relatively accessible; F3’s was further back in the mountains. I’d never been on a collar retrieval before, so I volunteered to go after M57’s. With telemetry receiver in hand, I figured it would be easy.

By the time the bears interrupted my search, I’d spent two afternoons in the vast meadow trying to pinpoint the telemetry signal, working off a single GPS point that the pilot had taken. It had been so easily within reach when Jason tested it back in the truck, a tame example of a technological object designed to do a task for humans, sitting benignly in the palm of Jason’s hand.

In the meadow, impossible to find and yet clearly somewhere nearby – the telemetry signal was persistent and loud – it seemed to have a devious life of its own, a capacity for illusion and elusion derived from the animal who had briefly worn it. I’d walk in the direction from which the signal seemed strongest; it would fade. I’d turn around and try again; the signal would appear to be coming from somewhere completely different. The previous afternoon a friend had gone with me, but even with her assistance in searching where I directed, we couldn’t find it. I was certain that Jason would have walked into the meadow and tracked down the collar within twenty minutes, but I’d never used telemetry to hunt for something in this way.

Preparing a collar for F3, March 2010

I’d finally found a strong signal and was following it downslope, closing in, when the bear juggernaut rolled across the meadow, across the path of the signal. The clock read 3:00 pm, and I had to be back in Jackson – many hours away – by the evening. I took it as a sign that the search was over. Sitting on the slope, I tried to keep an eye on each bear while simultaneously packing up the telemetry equipment. I accidentally kicked a few rocks downslope; the cinnamon bear froze and looked in my direction for a  second, before suddenly charging towards the black bear. The black bear evaded, and ran into the trees where I’d been standing looking for the collar. Summer, of course, is bear mating season, and as the black bear stood behind a tree and peeked out at the cinnamon bear, I realized that this could be courtship, which meant that I might be on the hill for a while. Then, the black bear turned and began walking up the slope towards me.

The telemetry equipment was still in disarray and at this point, I wasn’t sure where the cinnamon bear had gone; if I went down the other side of the hill, it might have circled around. I kicked a few more rocks loose, and then let the bear know I was there, speaking softly, which is what I had been told to do in a bear situation. Despite hours and hours on the trail, this was the first time I’d encountered bears out in the wilderness while alone. Black bears are much less intimidating than grizzlies, but I was still surprised by how calm and unthreatening the situation was. The bear looked up the hill, startled, and then wheeled and trotted into the trees on the far side of the meadow. I waited for a few more minutes, and when neither bear reappeared, I slid back down the ash-covered slope and then walked cautiously down through the meadow. The bears did not return. At the bottom of the meadow, I turned and asked that if either of them found a collar, they leave it there, so that when we came back, it would still be there to find.

Delectable Sheep

I camped out last night, and ran across a herd of twelve bighorn rams as the sun was setting.

Bighorn ram (Ovis canadensis), Wyoming

It occurred to me, as I delighted in looking at these sheep for purely asthetic reasons, that a wolverine would probably have a different reaction, namely: yum! Jason Wilmot speculates that there’s an as-yet-unproven relationship between mountain goat distribution and wolverine distribution, and we know that wolverines seem particularly fond of snacking on beavers, but wild sheep, as one of the few ungulates capable of surviving in high altitude terrain, also play a role in gulo’s diet. The Glacier Park study observed instances of wolverines eating sheep and, half a world away, a friend of mine watched a Mongolian wolverine chase argali sheep in Tavan Bogd National Park. Whether wolverines are actually hunting sheep, or opportunistically scavenging sheep remains, members of the Ovis genus are likely an important food source.

Speaking of chasing things, both F3 and M57 dropped the collars that we put on them this spring. I’ll be headed out on Saturday to try to retrieve M57’s collar, a last hurrah for this wolverine season before I leave for Mongolia on June 17th. I’ve never been on a collar retrieval before, but I understand that they can become exasperating, even when the collar is still sending out a signal and you can use telemetry to help find it. So keep your fingers crossed for a successful hunt and useful information once we get the collar back to the office.

Face to Face (F3 Capture, part 2)

(The first part of this narrative is here)

The degree of devotion required of wolverine biologists in the service of gaining knowledge would put the most pious of religious adherents to shame. En route to Montana along the deserted dead-of-night roads, Jason told stories of his previous years directing field operations for the Absaroka-Beartooth Project – tales of crossing Yellowstone on snowmobile to reach a capture site while the roads were closed, performing the collaring operation, and then turning around and snowmobiling back, narrowly avoiding collisions with bison and wolves in the dark; tales of six-hour searches for dens in icy sleet with no real clue where the den might be (they found it); tales of sticking his head into dens without any assurance that the mother wolverine wasn’t inside (she was); tales of broken ribs in snowmobile maintenance mishaps; many, many tales of having to sacrifice time with his family in order to be in the field doing things that no one else was able to do, so that we might learn what a wolverine was eating, or whether or not she was denning.

When I first met Jason, in March of 2006, he and his wife were running a research trapping operation, living in a remote cabin in Sunlight Basin, Wyoming, with their two-year-old daughter. Kate, his wife, was eight months pregnant; on the day I met her she told me she was headed out to ski up a pass to look the carcass of a skinned mountain lion that some hunters had killed the day before. ‘Intimidated’ doesn’t begin to describe the feeling that this family evoked. I thought they were crazily obsessed. But within six months I was paying my own tithes to the quest for wolverine data – I became so sick on my first wolverine trek that I could hardly walk, and spent a night on the cold ground in the middle of the wilderness at 11,000 feet – and finding myself in a truck laden with capture supplies, driving through a snowstorm along deserted roads at 2:00 in the morning, seemed a natural evolution. Once you’re hooked, you’re really hooked.

We arrived in Montana at 2:30 in the morning, slept for three hours, and were up and boiling water for the hot water bottles by 6:00. At 7:00, equipment packed and requisite eight layers of insulating clothing donned, we headed to the snowmobiles, and by 7:30 we were at the trap, where two members of the field crew, in another act of dedication, had spent the night camped out in the snowstorm to make sure that F3 was okay.

Unlike her placid companion M57, F3 was in full gulo mode from the moment she heard us approach. That indescribable, spine-tingling growl rumbled up from the trap before we even lifted the lid. When we knelt down to peer into the trap, she paced and growled, rushing the opening and our flashlights, drool trailing from her bared teeth. She was smaller than M57, but about ten times as ferocious. She strode between the back wall of the trap and the entrance, lunged, bit the flashlight (three dents; paint scraped clean off), paced to the back wall, and began tearing a piece of bait to shreds, keeping an eye on us as if to make sure we witnessed this demonstration of her ability to demolish anything she chose. In 2007, F3 chewed her way out of a log box trap through six inches of solid wood.  We took the point, and lowered the lid to prepare the drugs.

By 8:40, she was out, and Jason lifted her from the trap and placed her gently onto the prepared bed of hot water bottles. The first and most pressing question was definitively answering whether she had given birth, and we combed quickly through the fur of her belly. Smooth, flat, teats so indistinct that we had trouble locating them. F3 had not had kits. She might have been pregnant earlier in the year, but wolverines mate in spring and summer and hold the fetuses in suspension until winter, when they know whether there are adequate resources for raising kits; if so, the fetuses implant and the wolverine will give birth. If not, the fetuses are resorbed into the female’s body and she waits for a better year.

F3 is probably about four years old, which is just on the cusp of reproductive age. We know for sure that M57 was in her territory during the summer breeding period, and all winter we’ve had conversations – we’ve practically broken out champagne and cigars – speculating about the addition of two new baby wolverines to the Greater Yellowstone population. Documenting any reproduction in a rare species is cause for excitement, but in this case, understanding by what routes and to where the kits would disperse could provide valuable clues to understanding the overall population dynamics of Rocky Mountain wolverines.  The failure of these kits to materialize is disappointing, but it raises some interesting questions. Did F3 and M57 mate but resources prove too slim to support a mother and babies? If so, why? We suspect that F3 herself was born in the Absarokas, which means that the range is capable of supporting a reproductive female and her offspring. Was the lack of snow this year a problem?

Alternatively, a quick first glance at the genetics suggests that F3 and M57 could be closely related, even though he was first picked up in a field in Idaho, hundreds of miles from his current location. He and F3 share enough DNA to be father and daughter (unlikely, given that we suspect that they are roughly the same age), uncle and niece, or brother and sister. After his release in the Centennials, M57 made a pretty quick and decisive trip to his current location in the Absarokas – was he returning to known territory, a territory that he couldn’t previously occupy because his father was still resident? And if so, do wolverines have some sort of incest taboo that precludes mating with a close relative?

On the other hand, given their relative degrees of ferocity, perhaps M57 – related or not – simply decided that trying to get friendly with F3 was too much of a risk (maybe that’s what happened to his missing toes?)

F3 weighed in at 8.5 kilos. Her mask and lateral stripe were more distinct than M57’s had been. Her teeth were in perfect shape, all her toes accounted for, her coat thick. She had a few fleas – the field crew spent some time tracking them through her fur and herding them into tiny plastic vials, to be sent for analysis – but was otherwise in excellent shape. We took vitals every five minutes, and with a steady temperature of around 102°F, she was doing well.

Jason had a hard time adjusting the collar because F3’s neck was so small, but there was still time afterward to attempt to take blood. Jason and the field crew jabbed around with a needle for about five minutes but, unable to locate a vein, eventually gave up. We were quickly approaching the 40 minute mark – the moment when she would, supposedly, begin to come out of the drug haze – but Jason had dosed her for 9 kilos, which meant that we had a little extra time. She remained so soundly out of it that we had time to pass her gently from hand to hand to take photos. Wolverines are slippery, their skin seems loosely attached, and when I gripped her by the scruff and tried to lift her, she seemed to fall. I had the same feeling I get with babies, namely that I’m about to drop and injure something that I probably shouldn’t be holding in the first place.

Reversal drugs injected, we put her back in the trap, where she remained utterly motionless long enough for us to open the lid and take more photos of her stretched out on the ground. Jason went back to the trap to check on her several times. Handling wild animals is always nerve wracking because no matter how careful you are, there’s a risk that something might happen. Within a few minutes, however, she was moving, so we shut the lid and sat down in the snow to wait the requisite two hours.

A daylight collaring operation offered a rare opportunity to catch some good photos and video, so before we opened the trap, we stationed three people with still and video cameras at different angles to the trap entrance. I was crouched behind a tree and a snow bank a few yards in front the trap, hoping that she would run by me. The lid creaked up, and a few seconds passed, and then, like a periscope, the collar antenna emerged, followed by F3’s head. We had waited for about ten minutes for M57 to leave the trap; F3 took one look at freedom and then she poured out of the trap’s mouth and, in a blur of snow, streaked towards me. I didn’t realize it until I looked at the photos and videos later, but she actually headed directly towards me before catching sight of me and then veering to the left, around me, and then off into the woods. She took about five seconds to disappear.

F3 emerges....

....takes stock...


.....(in a blur of snow)....

....and disappears.

That was it, the culmination of the trapping season. While waiting for F3 to come out of the drugs, the field crew had taken down the hanging bait and snowmobiled to the other nearby traps to prop them open. We’d tossed pieces of beaver carcass and roadkilled elk into the woods for the enjoyment of the martens, the hungry emerging bears, and, hopefully, for F3 and M57. Once F3 disappeared into the trees, we propped open that trap, took down the automatic camera, and hauled out all the extraneous pieces of the trapping operation.

There was something bittersweet about driving back to Jackson, stopping in Mammoth to drop off a collection of items that had been on loan from Yellowstone to the Project. Officially, 2009 was the last year that the Absaroka-Beartooth Project was funded in association with Yellowstone. But with instrumented animals on the air, it would be a wasted opportunity not to continue monitoring. With the urgency of the field season at an end, the lull between research trapping and my upcoming trip to Mongolia to look for wolverines there will be occupied with a search for grants and private money to keep track of F3 and M57 next year. Meanwhile there are many important, looming questions about wolverine conservation and even, possibly, recolonization of Colorado, the answers to which will be partially provided by studying the populations in southern Montana and in Wyoming. Jason reflected that he felt it was the end of an era, but I hope that it’s simply a transition to a new set of research questions about an animal that will – if we can answer those questions – expand our understanding of what needs to be done to protect the montane ecosystems of the West.

(A video of F3’s capture and release may follow, so check back.)

The Collar (The Capture, Part 3)

(the first part of this narrative is here; the second part is here)

Seven minutes, and M57, the growling devil bear, was reduced to a heap of snoozing fur. Jason crawled into the trap and pulled him out; a potent wash of wolverine scent – somewhere between sweat and expensive goat cheese – drifted over the assembled crowd as we weighed him (12.4kg) and then lowered him onto the bed of water bottles and blankets. Quickly, the field crew secured M57’s feet, while Bob, Mark, and Jason slipped the oxygen mask over the wolverine’s face and fixed the pulse oxymeter to his tongue. I was trying to count his breaths, watching the rise and and fall of his chest; a moment of intense panic as it seemed that he wasn’t breathing at all. I saw Jason lean quickly forward, pushing aside the fur on the wolverine’s torso as if searching for a sign that the animal was still breathing, and then the breaths came, rapid and shallow.

M57’s initial readings were good – a temperature of 101°F, heart rate of 56 beats per minute, respiration at 48 breaths per minute, and a blood oxygenation rate that was steadily climbing as the oxygen mask took effect – so the crew took its time looking him over. He was dark, but not as dark as some wolverines; the face mask and the lateral stripe were faintly visible, the white chest patch prominent. His left front paw was entirely white, and his right front paw bore a crescent marking. Since his capture in the bobcat trap in Idaho in 2009, he’d lost two toes from his right front paw – one of these toes had been dislocated in the bobcat trap – but the wound was old and well-healed. At 12.4 kg, he was smallish for a male wolverine, but his weight was about the same as it had been when WCS had taken him to Montana, which was a good sign. Jason checked his teeth: lower left canine broken, with apparent cavity; top right incisor missing. Later, Jason said that most adult wolverines were missing teeth or had broken canines, which probably limits the lifespan of an animal that lives largely by its teeth.

Taking pictures of the foot with the missing toes

Together, Jason, Bob, and Mark assessed M57’s neck, where the fur was worn slightly, presumably from the previous collar. The skin was healthy, though, with no sores or other signs of damage. Before we got on the snowmobiles to head to the trap, the scientists and field crew had held a quick meeting to decide on procedure, and there was unanimous agreement that if there was any sign of injury from the previous collar, we would release M57 without putting on a new collar. But he seemed fine

Jason, Bob, and Mark quickly fitted the collar around M57’s neck, punching holes, making adjustments, while I kept track of the vitals; all signs remained good, the temperature never dropping below 100°, but we were running out of time, with only five or six minutes left. The collar rivets tightened, Jason asked for the list of measurements that we were supposed to take, and I read them off from the capture form. Total length: 109 cm. Tail length: 24 cm. Chest girth: 44.5 cm. Neck circumference: 34 cm. Head circumference: 33.5 cm. Jason seemed impatient with some of these measurements, and thankfully cut me off before we reached the final item on the list: circumference of testes. Noting that they were descended was apparently adequate for our purposes (we had high hopes that he and the resident female wolverine, F3, had mated. The two had been spotted within a mile of each other a few days previously, and both were around 4 years old, the perfect age to start reproducing. In the circumstances, knowing that he was capable of fathering kits was a crucial point; the precise parameters of his capacity seemed less important. Back in the office in Jackson, reviewing the forms, I asked Jason what the circumference of testes indicates within the context of wolverine biology, and he thought for a second, and said, “No idea.”)

We untied the wolverine’s paws and gently flipped him onto his stomach so that we could check for parasites. Time was running out, and suddenly M57 shuddered and began to growl, this time an outright snarl that seemed much less placid than his rumbling in the trap. This was the signal that the procedure was at an end. Keeping a firm hold on the animal’s head, Jason lifted him, one of the field crew quickly injected M57 with a drug reversal, and the crew snapped a few fast photos. By the time Jason and M57 reached the trap, M57 was struggling, and Jason lowered him carefully into the interior and then the lid came down.

That was it. We would wait for two hours to make sure that the drug had been fully metabolized before we released him. Most of the crew headed out, and those who remained tidied up the supplies, loaded them back into boxes and backpacks, and rehashed the evening in hushed voices. We spent some time looking at the tracks around the trap, and Jason mentioned that M57 had traveled to the trap following the exact same route that F3 habitually took. No one was sure what this indicated. Wolverines have a reputation for being solitary, but biologists suspect that they are more social than we’ve previously believed, and there’s speculation that male wolverines play a larger role in raising their kits than we realized. M57 and F3 had been in close proximity to each other a few days before M57 was captured, and they’d been spotted in similar proximity over the summer. It was difficult not to spin off into wildly anthropomorphic tales of a budding wolverine family. February is denning season, and if F3 was pregnant, she would have just given birth.

Periodically, we lifted the trap lid to check on M57. First he was asleep, curled up where Jason had placed him. Twenty minutes later, he was sitting a few feet from the mouth of the trap, staring but not growling. Later, he was pressed against the mouth of the trap but still seemed woozy. We closed the lid again, sat or leaned against the couch, watched the snow drift down. A pair of eyes, caught in the beam of the headlamp, glowed piercingly green against the night, coming down the path towards the trap, and for a second my heart thudded and my head went light; I was convinced it was F3 (A momentary diversion, the thought of a wolverine marital dispute: “Where have you been? Oh, you were kidnapped by aliens, that’s a likely story! You’re acting completely stoned. Are you high? My god, we have infants back at the den!”) Then a second pair of eyes appeared, and when we pulled out a flashlight, two martens stood still for a second in the beam before scampering into trees. Their eyes blinked at us from around the trap; first uphill to the left, then on the path again, then off to the right. They were after a chunk of bait that was hung from one of the trees. They huffed and circled and seemed momentarily confused by the sudden presence of people at what was clearly a habitual nightly feast, but, being weasels, they quickly decided that we weren’t a threat. The director of the field crew showed us a video, on his cell phone, of a marten they’d caught in one of the traps earlier in the winter; the animal, weighing in at around five pounds, seemed twice as aggressive as our wolverine, snarling, growling, screeching, and throwing itself towards the camera.

“You’re twenty, thirty times its size, and it still wants to take you,’ said the field crew director, ” Amazing.”

The green eyes glowed at us from the tree, and then from the bait, while the field crew director frowned. The bait was suspended several feet from the trunk of the tree to prevent scavengers from getting to it, but the martens were regularly able to pillage the supplies, and no one was sure how they were doing it. Now, in the beam of the flashlight, we watched them walk the suspension wire as if it was a tightrope. The field crew director shook his head. “They’re on the wire,” he said, “Amazing.”

The martens animated the night, and the shockingly brilliant glow of their eyes, here and then gone and then reappearing someplace completely new, conferred a sense of living intelligence, as if the ecosystem itself was watching us watch it.

At midnight, we checked M57 again, and he was growling and pacing once more. Jason propped open the trap lid and we stood back on the slope of the hill overlooking the trap, cameras poised, waiting. And waiting. And waiting. My camera batteries died in the cold, but I didn’t dare move to retrieve my smaller camera. Finally, M57 poked his head out of the trap, tentatively. He turned to look at us, and then retreated. We waited. For the first time that night, my toes were beginning to feel cold. I didn’t dare stamp my feet or do anything other than curl my toes inside my boots.

M57’s head emerged again, and again he turned to look at us, a long, flat stare. He’d been in the trap for hours, and for all of that time, danger had approached from the very place that we were now expecting his to use as an exit. He put his front paws on the lip of the trap, stretched up, and looked out towards the forest, then back at us. He stood like that for a long time before finally climbing out of the trap and, with one last look at us on the hill, dashing away. Except that he had run directly into the maze of the operating theater, where the crew had dug a series of high-walled passages into the waist-high snow. We stayed still, and a few minutes later M57 reappeared, looking chagrined, trying to find a way out of the passage. He climbed one wall, turned to stare, then zigzagged towards the pines. He looked huge against the snow as he ran. He suddenly stopped, turned in two tight circles, rolled over and over on his back. Then he stood up, and moved into the pines, crested the hill opposite, and disappeared.

The Zen Wolverine (The Capture, Part 2)

(part 1 of this narrative is here)

The log box trap, nestled into the snow beneath the towering pines, sat like a gift waiting to be opened. M57 was inside, quiet.  The field crew had determined that he wasn’t wearing a collar. They’d also, while waiting, dug an outdoor operating theater into the snow. And a couch. The couch faced the trap, and the entire setup could have been a piece of installation art, a wry and clever commentary on the fact that Americans spend too much time indoors, glued to the television or the computer.

The log box trap, with M57 inside

We carefully raised the lid of the trap, and there, dark against the dark of the trap except for glowing eyes in the beam of the flashlight, was M57. A gnawed bone was visible beside him, the remains of the roadkilled animal that had been used as bait. Log box traps were first used in a wolverine study  by wolverine biologist Jeff Copeland in Idaho; he needed something made of native materials with which a wolverine would be familiar, solid enough to hold the animal without harming it. The trap functions like this: a carcass of something (preferably a beaver; Jason is fond of saying that beavers are like candy to a wolverine, their favorite snack) is attached to a wire that, when pulled, releases the trap lid and closes the wolverine inside. The traps attract dozens of other, smaller carnivores – martens, fox, coyotes, ermine, bobcats – so the trigger is calibrated to the strength of a wolverine. The wire is attached to a radio transmitter, whose signal changes when the trap is triggered. This allows the field crew to monitor the traps remotely and to check on the traps in person when a lid is down. Although the trap is specialized for wolverines, tenacious small carnivores have been known to trip the mechanism, and the release of a marten or a fox is the more frequent beginning of the day than the capture of an actual wolverine.

M57 wasn’t happy about his imprisonment, but by wolverine standards, he wasn’t overly irate, either. He employed minimal ferocity as he ventured towards the front of the trap, the low, spine-tingling gulo growl that seemed like the misbegotten offspring of a housecat’s purr and an approaching thunderstorm. Jason held the flashlight and M57 paced and growled, clearly wanting out of the trap, but not venturing too close to the humans. On other captures, Jason said, the flashlights emerged covered in wolverine spit as the animals charged and attacked. Wolverines have also been known to chew their way out of log box traps if they are left for long enough. This was one of the reasons the field crew had sat on their couch and kept watch throughout the day. M57 hadn’t chewed much, but if he had, they might have placed a radio on top of the trap to keep him away from the walls. Wolverines may have an overly-inflated reputation for berserker insanity, but they are definitely capable of impressive tenacity and a high degree of havoc when necessary.

We left M57 to his meditations in the trap, and prepped the theater for the collaring, laying out all the necessary equipment on the broad snow table – lights, wool blanket, hot water bottles, a thermometer, the collar itself and a leather punch and wrench for fastening it, ties for the wolverine’s legs, a wide sock to slip over his eyes to help keep him calm. Mark and Bob, of WCS, had brought an oxygen tank and a pulse oxymeter, which was fortunate because ours wasn’t working. The pulse oxymeter, by way of a clip that attached to the tongue, would measure pulse, heart rate, and blood oxygenation levels while the wolverine was under. One of the field crew would take the temperature manually; these vitals had to be recorded every five minutes. With the drug combination used in wolverine captures, there is a risk of hypothermia (the drugs that biologists use with wolves, on the other hand, create a risk of overheating) and if the animal’s temperature began to drop, we would reverse the drug and put him back in the trap to recover. We were fortunate that it was a warm night, but we still prepared the water bottles and several packets of hand-warmers, which could be tucked into the wolverine’s joints if necessary.

Preparing the collar

Jason had delegated the job of injecting the wolverine to the chief of the field crew, a big moment since this is a tricky maneuver and, according to Jason, the highlight of the whole capture. To effectively sedate a wolverine, you have to distract the animal so that it doesn’t see the person preparing to give it the shot; otherwise it will face that person directly and make it impossible to get a good angle. You have to deliver the drugs quickly, which means that they have to be highly concentrated. And of course, you can’t get too close – who wants to stick their torso head-first into an enclosed space with a thirty-pound weasel?  – so the entire procedure is mediated by a meter-long stick, to which the syringe is attached. The jab requires force and conviction and you only get one chance.

While Jason distracted the wolverine with the flashlight, playing with the light and attempting to turn M57 the way a bullfighter might turn a bull, the head of the field crew stood at the opposite corner of the trap with the jabstick poised, waiting for a clear shot at a flank. M57 paced and growled and I watched from a safe distance as the light caught specific features – the lowset ears with their line of white fur, the small, intelligent eyes, a dark cheek framed by a faint mask, the broad, low forehead. Then a flurry of movement, the jabstick flashing forward, the wolverine flinching back, so fast that I didn’t think it could possibly have been a hit, but the head of the field crew was saying, “I got him. I got him. The full dose,” as the lid was lowered. Jason and the head of the field crew examined the empty syringe, and then Jason said, “Seven minutes.” I had the watch; it was 8:43 pm. We had exactly 40 minutes before M57 would wake up.