Wolf pup Canis lupus survival is a key driver of wolf population dynamics that remains poorly understood, especially in forested systems, because wolf pups are difficult to monitor. We used a combination of pup counts at dens and remote camera observations to estimate annual survival and recruitment of wolf pups in the Greater Voyageurs Ecosystem, MN, USA, from 2019 to 2025. We estimated recruitment for 33 packs over 92 pack-years and survival for 23 litters from 13 packs. Mean annual pup recruitment was 1.27 pups per pack, and mean annual pup survival was 0.29. Annual wolf pup recruitment and survival rates were highly variable among years and packs, which is likely a result of differences in food availability and the ability of breeding animals to acquire sufficient prey to provision dependent pups. Pup survival was negatively related to litter size. Although most (71%) wolf pups born during our study did not survive their first biological year, the population remained relatively stable, suggesting that recruitment rates were sufficient to sustain the high-density wolf population over time. Our work underscores the potential of integrative monitoring approaches to advance the understanding of wolf reproductive ecology.

Seed dispersal plays a key role in facilitating important ecological processes that reduce plant competition, parasitism and predation while promoting gene flow and biodiversity. In many ecosystems across North America and Eurasia, wolves consume fruits when available. However, the impact of wolf consumption on seeds, particularly germination success and speed, remains unknown. We extracted blueberry seeds from wolf scats and fresh fruits in the Greater Voyageurs Ecosystem, Minnesota, USA, where wolves forage extensively on blueberries in summer. We grew seeds under controlled conditions to assess if blueberry seeds deposited in wolf scat germinate more rapidly and successfully than seeds from berries alone (control). Seeds that passed through wolf digestive tracts had higher germination success and speed than controlled seeds. This pattern suggests blueberries receive positive benefits passing through wolf gastrointestinal systems. This finding, in combination with wolves' propensity to travel long distances in short periods, indicates wolves are likely effective long-distance dispersers of blueberry seeds. Thus, our findings reveal another way wolves are likely connected to larger ecological processes in boreal ecosystems, and possibly other ecosystems where wolves consume fruits.

Given the importance of protected areas for biodiversity, the growth of visitation to many areas has raised concerns about the effects of humans on wildlife. In 2020, the COVID-19 pandemic led to temporary closure of national parks in the United States, offering a pseudonatural experiment to tease apart the effects of permanent infrastructure and transient human presence on animals. We compiled GPS tracking data from 229 individuals of 10 mammal species in 14 parks and used third-order hierarchical resource selection functions to evaluate the influence of the human footprint on animal space use in 2019 and 2020. Averaged across all parks and species, animals avoided the human footprint, whether the park was open or closed. However, although animals in remote areas showed consistent avoidance, on average those in more developed areas switched from avoidance to selection when protected areas were closed. Findings varied across species: some responded consistently negatively to the footprint (wolves, mountain goats), some positively (mule deer, red fox) and others had a strong exposure-mediated response (elk, mountain lion). Furthermore, some species responded more strongly to the park closure (black bear, moose). This study advances our understanding of complex interactions between recreation and wildlife in protected areas.

Knowledge of wolf (Canis lupus)-beaver (Castor canadensis) interactions has largely been derived from indirect observations due to the cryptic nature of wolves and the densely forested areas where they usually kill beavers. In September 2023, we captured a video via remote camera of a wolf killing an adult beaver that was foraging on a feeding trail. This observation provides insight into how wolves may prevent beavers from reaching water after an attack is initiated, as well as how beavers attempt to escape once attacked. The camera also recorded the number of beavers foraging before and after the kill, providing a unique opportunity to observe the foraging behavior of the surviving beavers. The camera recorded videos on the trail for 11 nights before the predation and 37 nights after the predation. The time beavers spent on the feeding trail declined by 96% following predation. Although we present just a single observation, it raises an interesting question: is it possible or even plausible to think wolves might immediately alter where or the extent to which beavers forage through predation? We provide a detailed discussion on possibilities and highlight areas for future research.

ABSTRACTIn many southern boreal ecosystems of North America, wolves are the primary predators of white‐tailed deer, and white‐tailed deer are the primary prey of wolves. Furthermore, wolf–deer systems have and will continue to become more common as white‐tailed deer range continues expanding northward in North America. Despite this, there is little information on kill rates of wolves on deer (i.e., the number of deer killed per wolf per unit of time)—a fundamental metric of wolf predation on deer—and how kill rates vary with deer density, wolf density, and environmental conditions. We estimated kill rates of wolves on deer before, during, and after a historically mild winter in the Greater Voyageurs Ecosystem, Minnesota, USA. Kill rates of wolves on deer were low (0.009–0.018 deer/wolf/day) in fall, peaked in February (0.050 deer/wolf/day), and quickly declined to 0 deer/wolf/day by April. The kill rates of wolves on deer we observed in winter were some of the lowest kill rates of wolves on deer that have been documented. Wolves in the Greater Voyageurs Ecosystem appeared unable to catch and kill a sufficient number of deer to meet their daily energetic requirements during Winter 2023–2024, and thus most wolves likely lost weight during winter, a period when wolves are typically in peak physical condition. The rates of wolf predation we observed appeared to be well below those needed to decrease deer population density in the GVE. Thus, our work, in combination with numerous other studies, indicates winter conditions are the primary driver of deer population change in northern climates.

Wolves are opportunistic generalists that can respond quickly to new and unique food sources. Wolves in some ecosystems will consume berries and other fruits when they are abundant and available; however, many aspects of this behavior remain unknown. In the Greater Voyageurs Ecosystem (GVE), Minnesota, USA, wolves consistently consume berries, particularly blueberries, when they are available. We deployed remote cameras in blueberry patches to record wolves foraging on berries over several years. We captured footage of wolves of all age classes, social statuses, and sex foraging on blueberries alone or with other wolves. Our observations indicate berry consumption by wolves is a widespread behavior in the GVE and likely in similar southern boreal ecosystems. We hope our work spurs researchers across wolf range to examine whether berry consumption by wolves is a widespread and ubiquitous behavior for wolves.

Animals within social groups respond to costs and benefits of sociality by adjusting the proportion of time they spend in close proximity to other individuals in the group (cohesion). Variation in cohesion between individuals, in turn, shapes important group-level processes such as subgroup formation and fission-fusion dynamics. Although critical to animal sociality, a comprehensive understanding of the factors influencing cohesion remains a gap in our knowledge of cooperative behavior in animals. We tracked 574 individuals from six species within the genus Canis in 15 countries on four continents with GPS telemetry to estimate the time that pairs of individuals within social groups spent in close proximity and test hypotheses regarding drivers of cohesion. Pairs of social canids (Canis spp.) varied widely in the proportion of time they spent together (5%-100%) during seasonal monitoring periods relative to both intrinsic characteristics and environmental conditions. The majority of our data came from three species of wolves (gray wolves, eastern wolves, and red wolves) and coyotes. For these species, cohesion within social groups was greatest between breeding pairs and varied seasonally as the nature of cooperative activities changed relative to annual life history patterns. Across species, wolves were more cohesive than coyotes. For wolves, pairs were less cohesive in larger groups, and when suitable, small prey was present reflecting the constraints of food resources and intragroup competition on social associations. Pair cohesion in wolves declined with increased anthropogenic modification of the landscape and greater climatic variability, underscoring challenges for conserving social top predators in a changing world. We show that pairwise cohesion in social groups varies strongly both within and across Canis species, as individuals respond to changing ecological context defined by resources, competition, and anthropogenic disturbance. Our work highlights that cohesion is a highly plastic component of animal sociality that holds significant promise for elucidating ecological and evolutionary mechanisms underlying cooperative behavior.

Evaluating methods used to capture and mark neonates is necessary for ensuring research methods are ethical, follow best practices, and do not have long‐term unintended impacts on neonates or populations. We used a quasi‐experimental approach (reference versus treatment) to determine whether visiting wolf dens and marking wolf Canis lupus pups affects important wolf population metrics. Specifically, we examined whether pup recruitment and pack size differed between packs where we visited dens and handled pups (‘disturbed packs' = treatment group) and those where we did not visit dens (‘undisturbed packs' = reference group). During 2019–2023, we studied 43 wolf packs and litters, 19 of which were disturbed packs and 24 of which were undisturbed. We found no difference in recruitment or pack size between disturbed and undisturbed wolf packs. However, we did observe substantial annual variation in recruitment and pack size, which indicated that other ecological factors (e.g. prey abundance) were likely responsible for annual changes in recruitment and pack size. Our findings are consistent with several other studies, and together this research indicates that wolf dens can be visited once and wolf pups handled briefly for research purposes without having a measurable effect on recruitment and pack size.

Cooperative hunting can confer fitness benefits by increasing foraging efficiency. We documented a breeding pair of wolves in the Greater Voyageurs Ecosystem of Minnesota, USA that appeared to periodically use cooperative ambushing to hunt beavers. The breeding pair primarily chose to wait-in-ambush close to one another (< 65 m) but on different beaver feeding trails, which appears advantageous because: (1) feeding trails are where beavers are most active and vulnerable on land, (2) the probability that the pair encounters a beaver is increased, and (3) either wolf can quickly assist the other in killing a beaver. The cooperative ambush strategy these wolves used appears rare for most social Carnivora but we hypothesize this behavior is widespread in areas of wolf-beaver sympatry. This observation demonstrates that novel insights into the natural history of even well-studied predators are possible when technological advancements are combined with intensive fieldwork.

Anthropogenic linear features allow wolves to travel faster and more efficiently, which is thought to increase wolf hunting efficiency of ungulates. Most previous studies have evaluated the role of linear features in wolf-ungulate dynamics by relying on indirect observations (e.g., GPS location data). Thus, there remains little direct observational data showing how wolves use linear features to hunt ungulates. Here, we present observational data (29 hunting sequences) of wolves using linear features to hunt ungulates. Linear features have largely been considered travel corridors that facilitate wolf movement and allow wolves to detect prey near (but not necessarily on) linear features. However, we clearly demonstrate wolves also use linear features as active hunting arenas where they detect, pursue, and kill prey that are also traveling directly on linear features. Our observations further suggest one of, if not the, primary way wolves detect ungulates on linear features is via olfactory cues.

Transboundary movement of wildlife results in some of the most complicated and unresolved wildlife management issues across the globe. Depending on the location and managing agency, gray wolf ( Canis lupus ) management in the US ranges from preservation to limited hunting to population reduction. Most wildlife studies focus on population size and growth rate to inform management, but relatively few examine species biological processes at scales aside from that of the population. This is especially important for group-living species such as the gray wolf, for which the breeding unit is the social group. We analyzed data for gray wolf packs living primarily within several US National Park Service units (years of data): Denali National Park and Preserve (33 years), Grand Teton National Park (23 years), Voyageurs National Park (12 years), Yellowstone National Park (27 years), and Yukon-Charley Rivers National Preserve (23 years). We identified two gray wolf biological processes that differed from population size – namely, pack persistence and reproduction – and determined that while human-caused mortality had negative effects on both, pack size had a moderating effect on the impacts of mortality.

Through global positioning system (GPS) collar locations, remote cameras, field observations and the first wild wolf to be GPS-collared with a camera collar, we describe when, where and how wolves fish in a freshwater ecosystem. From 2017 to 2021, we recorded more than 10 wolves (Canis lupus) hunting fish during the spring spawning season in northern Minnesota, USA. Wolves ambushed fish in creeks at night when spawning fish were abundant, available and vulnerable in shallow waters. We observed wolves specifically targeting sections of rivers below beaver (Castor canadensis) dams, suggesting that beavers may indirectly facilitate wolf fishing behaviour. Wolves also cached fish on shorelines. We documented these findings across five different social groups at four distinct waterways, suggesting that wolf fishing behaviour may be widespread in similar ecosystems but has probably remained difficult to study given its annual brevity. Spawning fish may serve as a valuable pulsed resource for packs because the spring spawning season coincides with low primary prey (deer Odocoileus virginianus) availability and abundance, and when packs have higher energetic demands owing to newly born pups. We demonstrate the flexibility and adaptability of wolf hunting and foraging behaviour, and provide insight into how wolves can survive in a myriad of ecosystems.

Predators are widely recognized for their irreplaceable roles in influencing the abundance and traits of lower trophic levels. Predators also have irreplaceable roles in shaping community interactions and ecological processes via highly localized pathways (i.e. effects with well‐defined and measurable spatio–temporal boundaries), irrespective of their influence on prey density or behavior. We synthesized empirical and theoretical research describing how predators – particularly medium‐ and large‐sized carnivores – have indirect ecological effects confined to discrete landscape patches, processes we have termed ‘patchy indirect effects (PIEs) of predation'. Predators generate PIEs via three main localized pathways: generating and distributing prey carcasses, creating ecological hotspots by concentrating nutrients derived from prey, and killing ecosystem engineers that create patches. In each pathway, the indirect effects are limited to discrete areas with measurable spatial and temporal boundaries (i.e. patches). Our synthesis reveals the diverse and complex ways that predators indirectly affect other species via patches, ranging from mediating scavenger interactions to influencing parasite/disease transmission risk, and from altering ecosystem biogeochemistry to facilitating local biodiversity. We provide basic guidelines on how these effects can be quantified at the patch and landscape scales, and discuss how predator‐mediated patches ultimately contribute to landscape heterogeneity and ecosystem functioning. Whereas density‐ and trait‐mediated indirect effects of predation generally occur through population‐scale changes, PIEs of predation occur through individual‐ and patch‐level pathways. Our synthesis provides a more holistic view of the functional role of predation in ecosystems by addressing how predators create patchy landscapes via localized pathways, in addition to influencing the abundance and behavior of lower trophic levels.

The demands of raising dependent young can influence the feeding behaviors of social carnivores, especially for individuals that are primarily responsible for provisioning young. We investigated how the feeding and provisioning behavior of a social carnivore, gray wolves (Canis lupus), are connected and shaped by extrinsic and intrinsic factors, and whether and how these patterns changed throughout the pup-rearing season (April-August). We found breeding wolves had shorter handling times of prey, lower probability of returning to kills, and greater probability of returning to homesites after kills compared to subordinate individuals. However, the feeding and provisioning behaviors of breeding individuals changed considerably over the pup-rearing season. Wolves had longer handling times and returned to provision pups directly after kills less frequently as annual prey abundance decreased. These patterns indicate that adult wolves prioritize meeting their own energetic demands over those of their pups when prey abundance decreases. We suggest that differential provisioning of offspring based on prey abundance is a behavioral mechanism by which group size adjusts to available resources via changes in neonate survival.

Predators can directly and indirectly alter the foraging behaviour of prey through direct predation and the risk of predation, and in doing so, initiate indirect effects that influence myriad species and ecological processes. We describe how wolves indirectly alter the trajectory of forests by constraining the distance that beavers, a central place forager and prolific ecosystem engineer, forage from water. Specifically, we demonstrate that wolves wait in ambush and kill beavers on longer feeding trails than would be expected based on the spatio-temporal availability of beavers. This pattern is driven by temporal dynamics of beaver foraging: beavers make more foraging trips and spend more time on land per trip on longer feeding trails that extend farther from water. As a result, beavers are more vulnerable on longer feeding trails than shorter ones. Wolf predation appears to be a selective evolutionary pressure propelled by consumptive and non-consumptive mechanisms that constrain the distance from water beavers forage, which in turn limits the area of forest around wetlands, lakes and rivers beavers alter through foraging. Thus, wolves appear intricately linked to boreal forest dynamics by shaping beaver foraging behaviour, a form of natural disturbance that alters the successional and ecological states of forests.

Humans are increasingly recognized as important players in predator-prey dynamics by modifying landscapes. This trend has been well-documented for large mammal communities in North American boreal forests: logging creates early seral forests that benefit ungulates such as white-tailed deer (Odocoileus virginianus), while the combination of infrastructure development and resource extraction practices generate linear features that allow predators such as wolves (Canis lupus) to travel and forage more efficiently throughout the landscape. Disturbances from recreational activities and residential development are other major sources of human activity in boreal ecosystems that may further alter wolf-ungulate dynamics. Here, we evaluate the influence that several major types of anthropogenic landscape modifications (timber harvest, linear features, and residential infrastructure) have on where and how wolves hunt ungulate neonates in a southern boreal forest ecosystem in Minnesota, USA. We demonstrate that each major anthropogenic disturbance significantly influences wolf predation of white-tailed deer fawns (n = 427 kill sites). In contrast with the "human shield hypothesis" that posits prey use human-modified areas as refuge, wolves killed fawns closer to residential buildings than expected based on spatial availability. Fawns were also killed within recently-logged areas more than expected. Concealment cover was higher at kill sites than random sites, suggesting wolves use senses other than vision, probably olfaction, to detect hidden fawns. Wolves showed strong selection for hunting along linear features, and kill sites were also closer to linear features than expected. We hypothesize that linear features facilitated wolf predation on fawns by allowing wolves to travel efficiently among high-quality prey patches (recently logged areas, near buildings), and also increase encounter rates with olfactory cues that allow them to detect hidden fawns. These findings provide novel insight into the strategies predators use to hunt ungulate neonates and the many ways human activity alters wolf-ungulate neonate predator-prey dynamics, which have remained elusive due to the challenges of locating sites where predators kill small prey. Our research has important management and conservation implications for wolf-ungulate systems subjected to anthropogenic pressures, particularly as the range of overlap between wolves and deer expands and appears to be altering food web dynamics in boreal ecosystems.

One of the most common and ubiquitous methods to age mammals is by counting the cementum annuli in molars, premolars, incisors, or canines. Despite the ubiquity and perceived simplicity of the method, cementum annuli analysis can be time-consuming, expensive, inaccurate, and imprecise, and require specialized equipment. Using beavers (Castor canadensis) as a test species, we developed a straightforward method to age mammals that requires little specialized equipment. The method consists of: (1) digitizing longitudinally sectioned teeth and measuring the proportion of tooth surface area comprised of cementum ( "proportion cementum "), (2) evaluating the relationship between proportion cementum and specimen age (determined from either known-age samples or cementum annuli analysis), and (3) using the modeled relationship to estimate the age of other individuals based solely on proportion cementum. The relationship between proportion cementum and age was strongly correlated (R-2 = .97-.98 depending on observer), similar between observers, and similar between known-age specimens and those aged via cementum annuli analysis. Using this proportion cementum method, two independent observers accurately predicted the age of 80%-84% of specimens within 0.5 year and 96%-98% within 1 year. We suggest this aging method will likely work with most mammal species given the relatively consistent deposition of cementum throughout mammals' lives and has promise to be a simple and quick alternative to cementum annuli analysis regardless of whether one develops proportion cementum models using known-age specimens or those aged via alternative methods.