In a groundbreaking new study published in the renowned scientific journal Oikos, researchers have unveiled a critical ecological role played by polar bears far beyond their status as top Arctic predators. The study, conducted by a multidisciplinary team from the University of Manitoba, San Diego Zoo Wildlife Alliance, Environment and Climate Change Canada, and the University of Alberta, quantitatively demonstrates that polar bears serve as essential providers of carrion, supplying millions of kilograms of wildlife resources annually to a vast network of Arctic scavengers. This finding reshapes our understanding of the Arctic marine-terrestrial food web and underlines the cascading impacts that declines in polar bear populations may have on the broader ecosystem.
Traditionally, polar bears have been recognized primarily for their role as apex predators, hunting seals on sea ice and regulating marine mammal populations. This new research, however, highlights a less appreciated but ecologically significant function: the transfer of marine-derived energy to terrestrial and ice-associated scavengers through the remains of their prey. The researchers estimate that polar bears annually leave behind approximately 7.6 million kilograms of seal carcasses, feathers, and other organic matter on the sea ice surface, which constitutes a massive nutritional subsidy accessible to numerous vertebrate scavenger species.
The interface where polar bears hunt—primarily the shifting sea ice—acts as a crucial platform bridging the ocean and terrestrial ecosystems. When polar bears drag their seal kills from the marine environment to the ice, they effectively relocate energy and nutrients offshore. This process sustains a rich community of arctic scavengers that might otherwise struggle to find reliable food sources in the extreme polar environment. Among the documented beneficiaries are species such as Arctic foxes and ravens, which rely heavily on the carrion provided by polar bear kills for survival during the harsh Arctic winter.
Lead author Holly Gamblin, a PhD candidate at the University of Manitoba, emphasized the uniqueness of polar bears’ ecological role. She noted, “No other species exhibits the distinctive hunting behavior of polar bears whereby prey are taken from the sea and deposited on ice platforms, creating a persistent resource base for other animals. Our work provides the first quantitative assessment of the magnitude of resources made available through this pathway.” This behavior not only sustains scavenging communities but also fosters intricate trophic interactions critical for maintaining ecosystem stability in rapidly changing polar landscapes.
The study’s findings carry significant implications for conservation biology and Arctic ecosystem management. The polar ice is melting at unprecedented rates due to climate warming, resulting in diminishing sea ice platforms that are essential not only for polar bear hunting but also for the access scavengers have to carrion. Declines in sea ice and polar bear populations are deeply interconnected, as fewer bears translate to reduced carrion availability. Researchers have already observed that decreases in polar bear abundance in two monitored subpopulations correlate with a loss of more than 300 metric tonnes of scavenger-accessible food annually.
Dr. Nicholas Pilfold of the San Diego Zoo Wildlife Alliance, one of the study’s co-authors, underscored the broad ecological ramifications: “Our data illuminate an often overlooked ecological service provided by polar bears. When the sea ice platform collapses, it disrupts this vital energy transfer, imperiling not just polar bears but entire food webs dependent on their carrion.” This interdependence suggests that polar bear conservation is pivotal for sustaining biodiversity and ecological function across extensive Arctic regions.
By quantifying the energy flow facilitated by polar bears, the research expands scientific appreciation for keystone species and their roles in ecosystem connectivity. The Arctic’s harsh environment means that nutrient pulses like carrion deposited on ice are disproportionately important for sustaining diverse wildlife communities. The study also spotlights the Arctic as an interconnected mosaic of marine and terrestrial food webs, wherein trophic linkages formed by apex predators have profound ripple effects reaching multiple trophic levels.
Beyond immediate ecological consequences, the decline of polar bear populations may prompt shifts in predator-prey dynamics and scavenger behavior. The loss of predictable carrion sources could force scavengers to adapt by either expanding foraging ranges or shifting to less nutritious alternatives, potentially leading to reduced fitness and population declines. Moreover, such shifts may cascade down to affect vegetation and invertebrate communities, illustrating the intricate interdependencies threading through Arctic ecosystems.
The researchers call for integrative conservation strategies that consider the full scope of polar bears’ ecological functions. Protecting polar bear populations and preserving sea ice habitat thus serve dual purposes: safeguarding a charismatic endangered species and maintaining essential ecological processes sustaining Arctic biodiversity. This integrative perspective demands global climate action and targeted wildlife management informed by interdisciplinary science.
This study aligns with ongoing efforts to understand and mitigate the impacts of climate change on fragile Arctic environments. It provides compelling evidence that biodiversity loss in polar regions cannot be viewed in isolation; instead, species declines reverberate widely through ecological networks, underscoring cascading vulnerabilities. The comprehensive approach taken by the research team—combining field data, ecological modeling, and collaborative expertise—represents a template for advancing Arctic conservation science in the Anthropocene.
The extensive contributions of polar bears as marine carrion providers add a critical dimension to their ecological narrative—one that emphasizes their integral role as ecosystem engineers and facilitators of energy transfer. Safeguarding this keystone functionality underlines the overarching necessity of preserving both species and the environmental conditions upon which they depend. As Arctic ecosystems face unprecedented transformation, understanding such complex species interactions becomes an urgent priority for researchers and policymakers alike.
In summation, this pioneering research redefines the polar bear’s ecological niche by quantifying its role in sustaining a wide array of Arctic scavengers through carrion provisioning. It sheds light on the interconnectedness and fragility of polar ecosystems, accentuating the multi-faceted consequences of climate-induced sea ice loss and polar bear population declines. The study calls for renewed conservation commitments recognizing polar bears not only as majestic predators but as essential contributors to Arctic ecological resilience.
Subject of Research: Animals
Article Title: Predators and scavengers: Polar bears as marine carrion providers
News Publication Date: 28-Oct-2025
Web References: DOI: 10.1002/oik.11628
Image Credits: Photo Credit Wayne Lynch
Keywords: Arctic ecosystems, Animals, Carnivores, Megafauna, Vertebrates, Wildlife, Wild populations, Conservation ecology, Trophic levels, Predation, Endangered species, Bears, Arctic ice
