When I woke, it was still dim inside the cabin of the small sailboat I shared with my husband and sons, aged 4 and 6. Wiping condensation from the porthole above my head, I peered out to scan for wolves. The previous evening, we’d watched a lone adult and four pups wrestle in the tall grass nearby. Now, all that remained was mist swirling against the steep fjord walls.
We were anchored in Shag Cove, a narrow inlet in Glacier Bay National Park, centered between the Gulf of Alaska on one side and the world’s largest intact temperate rainforest on the other. As a biologist, I’ve made many forays to watch wildlife in the rain. But this time, I wasn’t here on scientific assignment. I’d sailed with my family from Haines, Alaska, to explore our watery backyard.
After breakfast, we rowed the dinghy to shore for a hike. As our boots squelched in the mud, a bald eagle flushed from the grassy meadow in front of us, its broad wings flapping noisily overhead. Curious about the eagle’s location, I scanned the grass with my binoculars. Instead of the salmon carcass I expected, I saw a wolf pup, lying dead on its back.
Though it’s not unusual to find dead things when you’re roaming Alaska’s coastlines, a fresh wolf carcass was certainly rare. As we approached, the boys froze, staring at the pup’s inverted pale skin and charcoal fur; even from a distance, the carnage was obvious. I was tempted to shield their eyes, but then I recalled a phrase I’d overheard from my son’s first-grade lessons: Every living thing has a life cycle, even us. We walked closer.
The scene offered few clues about the wolf’s demise. I saw no evidence to suggest it had been killed by a larger predator — no bear tracks or drag marks, only torn bits of flesh that the eagle had ripped from its lean body. My older son’s brown eyes stretched wide beneath the cinched hood of his rain jacket, while my younger son clutched my husband’s hand, his lower lip pushing out the way it always did just before he turned to tears.
“Why?” they asked. And then: “Are the other wolves OK?”
Though it’s not unusual to find dead things when you’re roaming Alaska’s coastlines, a fresh wolf carcass was certainly rare.
From my perspective as a biologist who studies wildlife health in Alaska, there has been precious little to celebrate in recent years. Each discovery we made seemed bleaker than the last: seabird carcasses washed up in windrows along the coast, humpback whales missing from their usual haunts, salmon runs the worst they’d been in a hundred years. Perhaps the pup was yet another casualty of an ecosystem in distress.
I felt like turning away from the gruesome scene. Instead, I did what both motherhood and science demanded: Stay calm and state the facts. I didn’t know the answers to my sons’ questions, but I knew something about wolves. And I had recently read a heartening report about the adaptability and resilience of another pack that lived nearby. Wolves were resourceful, I told my teary-eyed boys, assuring them that the rest of this pup’s family would likely find a way to survive. Only later would I learn just how creative some of these island-hopping carnivores could be.
Pleasant Island is two miles from the town of Gustavus, Alaska, and less than 30 miles from where we’d anchored. A wolf pack arrived there in 2013, after swimming across the narrow channel from the mainland. Initially, they did what wolves typically do: eat every ungulate they could clamp their jaws around. After they’d decimated the island’s limited deer population, their next act seemed obvious: The pack would move, or starve. Several decades earlier, an ill-fated and ethically dubious ecological experiment on Alaska’s far-flung Coronation Island demonstrated what happens when introduced wolves eat all the local deer and have nowhere else to go: In the absence of prey, the wolves starved, resorting to cannibalism before eventually dying out entirely.
But, as Juneau-based biologist Gretchen Roffler and her colleagues revealed in a pair of studies published in 2021 and 2023, the Pleasant Island wolves found another way. When deer disappeared from the menu, the pack shopped around, and did so with remarkable success.
Roffler’s first glimpse of a Pleasant Island wolf eating a sea otter seemed like an anomaly. But when she observed the same behavior again, she suspected a larger phenomenon might be at play. To test this, she and her colleagues began the unglamorous work of scooping poop from the island’s beaches and forested trails. By analyzing the scat’s carbon and nitrogen isotopic signatures, akin to fingerprinting tools for feces, they could determine whether the wolves were eating terrestrial herbivores, like deer, or marine predators, like seals or otters. Combining this research with on-the-ground field observations and GPS collars that tracked the wolves, they found that the pack was not merely sampling otters; they were devouring them en masse. Despite being fierce adversaries, with sharp teeth and claws, otters provided the wolves with a reliable alternative to venison.
Wolves are known to be opportunistic, but this pack’s quick and dramatic prey shift sent shock waves through the wildlife world
The sea otters were relative newcomers themselves. After near-extirpation throughout much of the North Pacific, otters were reintroduced to the outer islands of Southeast Alaska in the 1960s, and their population rapidly expanded. Whether the first Pleasant Island otter meal was a lucky accident or the result of a strategically planned hunt, the pack wasted no time in capitalizing on this now-abundant resource. In 2015, wolf scats collected from the island consisted of approximately 98% deer; by 2018, deer had disappeared entirely and sea otters made up more than two-thirds of their diet.
Though what wolves eat for lunch might not seem revolutionary, this demonstration of their flexibility is, particularly when it comes to shaping our scientific understanding of their lives. Wolves are known to be opportunistic, but this pack’s quick and dramatic prey shift sent shock waves through the wildlife world: in just three years, they’d upended classic predator-prey dynamics and bent the supposed “rules” of their lives.
Most wolves specialize on ungulates, including deer, moose and elk. Pleasant Island’s wolves seemed no different until they amended the core tenets of this long-standing exchange, and did so in a matter of just a few years. By crossing a dietary threshold, they had propelled themselves across ecotones and trophic levels — switching their primary food source from a bottom-up terrestrial herbivore (deer) to a top-down marine carnivore (otters). This isn’t just a matter of semantics; conserving the health of wildlife populations requires knowledge about what animals eat, where they live, and what they might do next. And these island-hopping wolves were full of surprises.
The pack’s novel hunting behavior revised not only their menu but biologists’ understanding of local ecosystem dynamics. Generally, the lives of forest-dwelling deer and urchin-loving otters have little in common. However, when wolves entered the scene on Pleasant Island, an important new link emerged: Where otters roamed, deer could not. Prior to the pack’s arrival, deer were regular residents on the island. As on Coronation Island, once the Pleasant Island wolves chomped all the available prey, they would have starved or left, allowing the deer to return and repopulate the island. But when the wolves instead discovered otters as a steady alternative food source, the pack flourished. An island full of wolves is no place for deer, and so Pleasant Island has become wolf country, with no deer allowed.
These new otter-wolf-deer connections have reshaped their shared home, with reverberations echoing both on land and at sea. Without deer to graze them, understory plants can grow largely unchecked on Pleasant Island, changing the forest structure and affecting habitat for other wildlife. Sea otters, in turn, are keystone predators of marine nearshore environments; in their absence, urchins can proliferate, destroying kelp forests and reducing biodiversity. It’s not yet clear whether terrestrial predators like wolves might eat enough sea otters to cause ripples through other parts of the marine ecosystem, but such impacts are plausible.
Though they made headlines in 2022 for their stark and rapid dietary pivot, Pleasant Island’s wolves don’t appear to be unique in their fondness for marine mammals. In Katmai National Park, for example, both wolves and brown bears have learned to stalk sea otters and seals, focusing their efforts on predictable haul-out locations during low tide. Wolves are famous for their cursorial (chase) tactics, but in some cases ambushing their prey may be more effective, as they’ve demonstrated in Katmai. Kelsey Griffin, along with Gretchen Roffler and another colleague, witnessed several instances of wolves positioning themselves near tidal streams or on rocky islets prior to successful hunts; one lone wolf even snatched a seal by the tail as it was swimming out of the creek with an outgoing tide. These strategies, the biologists argued in a study published in The Scientific Naturalist, suggest that wolves are using “planning and foresight of future events to position themselves for a successful ambush.”
Elsewhere, wolves use ambush techniques to catch freshwater fish. In the boreal lake systems of the Greater Voyageurs Ecosystem of northern Minnesota, biologists recently documented wolves hunting perch, pike and other fish species with strategies similar to those of the Katmai wolves: choosing an ambush location based on its physical characteristics — in this case, in shallow waters, often downstream of beaver dams. One wolf was observed pulling out multiple fish in a row from the same location, reminiscent of an angler plying her favorite fishing hole. As in Alaska, linkages across Minnesotan ecosystems extend well beyond the traditional two-party predator-prey system. Beaver dams facilitate wolves’ ability to fish successfully by creating shallow water systems in which wolves can not only see the fish, but hear them, a critical component for fishing under the cover of darkness. This intriguing cross-species dynamic — beaver-assisted nocturnal fishing — is further complicated by the fact that wolves also sometimes eat beavers, and in doing so change their wetland environment by removing one of its key ecosystem engineers.
Wherever wolves roam, they leave complex ecological footprints. At our cabin near Haines, we’ve watched members of a resident pack chomp spawning pink salmon, favoring the fat-rich heads and discarding the rest. In doing so, they not only feed their young, but the forests, too. When wolves — along with bears, eagles and other animals — drag carcasses to shore or eat salmon and poop out their remains in the woods, they deliver resources to the terrestrial environment, enriching everything from trees to bugs to songbirds. On land, wolf-hunted ungulate carcasses can serve as nutrient hotspots while simultaneously raising hackles among livestock owners and big-game hunters.
The idea that carnivores’ dietary habits can influence their environments isn’t new. However, as our awareness of wolves’ ability to shift what they eat — quickly and sometimes dramatically — grows, so does the need for a more nuanced scientific approach. Traditionally, ecological theory has prioritized models that simplify relationships in the wild: Wolves dine on ungulates, predators need prey, and the lives of deer, beavers and otters have little in common. However, otter-eating wolves and other so-called exceptions may actually be teaching us just how capable some species are of responding rapidly when the need arises. Ecologists sometimes refer to this potential to pivot as “adaptive capacity;” i.e., how fast a species can change the rules of its own game.
In the case of our dead wolf pup, Steve Lewis, a biologist who studies eagles in Alaska, suggested that perhaps it had been targeted by the eagle we saw eating it. We’ll never know exactly what happened that day in Shag Cove, but with salmon runs in the region cratering, eagles must also get creative. Bald eagles that live along the Pacific Coast are largely dependent on fish, but they, too, have been observed stretching their dietary wings to include everything from deer to seal pups to small dogs. As with the otter-eating wolves, there’s a narrow margin between anomaly and true behavioral flexibility. However, this seemingly esoteric distinction has important practical applications: Our understanding of how natural systems work dictates how we manage them for conservation. As we attempt to protect species and habitats for our children’s generation, failing to take into account the messy details means getting it wrong now, and perhaps forever.
In a time of ever-worsening environmental news, there’s a bright spot emerging from these discoveries: Wolves — a species with a history of intense persecution — are writing a part of their own ending to the story. They’re also reminding us that the “messy details” of animals’ lives might in fact be the postscript we need to better understand our future. It’s these very anomalies that offer glimmers of hope in the Anthropocene: Animals may be capable of more than we yet understand.
Seven months after our stay in Shag Cove, on a return trip to Glacier Bay, we sailed past the southern coast of Pleasant Island. From a distance, it looked like any other island in Southeast Alaska, a tree-lined silhouette holding its secrets close to its chest. As I scanned the shoreline for wolves, my younger son pointed out a raft of sea otters floating nearby.
“Look, mom, it’s wolf lunchtime.”
My children had pushed me for answers; in the process, I’d learned something new about wolves, and, in turn, how many surprises remain to be discovered. As we face a future of uncertainty, let the trout-eating, sea otter-stalking, seal-dragging wolves be an example to us all: There is more than one way to end even the tales we think we know best.
