The research, published in Frontiers in Ethology, was led by Elisa Torretta of the University of Pavia and colleagues, who compared the feeding ecology of wolves in two sharply contrasting sectors of north-western Italy’s Lombardy region. The Lombard Apennines represent the species’ historical range in the area, occupied since the late 1980s, while the Po Plain, a mosaic of intensive agriculture crisscrossed by the wooded corridor of the Ticino River, has been colonized only recently, with the first resident lowland packs confirmed in 2021 to 2022. By 2025, researchers had documented reproduction in thirteen packs in the Province of Pavia, eight in the Apennines and five in the Plain, plus four packs in the neighboring Province of Lodi, with a mean pack size of 6.6 individuals.

Between 2021 and 2025 the team collected and analyzed 1,078 wolf scats, 792 from the Apennines and 286 from the Plain. Sampling followed a non-invasive protocol: the study area was divided into 25-square-kilometer grid cells, and 61 fixed routes along footpaths and dirt roads, averaging 5.6 kilometers in length, were walked four times per year by trained personnel. Scats were identified in the field by size, shape, and location, and their contents, hairs, bones, hooves, claws, mandibles, and seeds, were examined microscopically against reference collections and published identification keys. As a countercheck, 38 samples collected between 2022 and 2025 were subjected to molecular species identification, and every one was confirmed as wolf, with no dog or red fox samples slipping in.

The headline result is striking: across both sectors and all five years, the diet remained overwhelmingly composed of wild prey. Livestock consistently contributed only a tiny fraction of consumed volume, peaking at just 2.4 percent in the Apennines in 2025, and domestic pets were almost entirely absent, with dog remains appearing in a single Plain year at 2.9 percent and cat traces negligible. This pattern held despite the Plain offering not only livestock and pets but also potential subsidies such as carcass remains and waste associated with intensive, stall-fed farming systems. The finding aligns with a broader European literature showing that where wild prey are abundant, wolves treat domestic animals as a secondary or minor resource, and that reliance on livestock can decline over time as wild prey populations provide year-round food.

What did differ dramatically was which wild animals the wolves were eating. In the Apennines, wild ungulates dominated the diet, contributing between 82.7 and 94.8 percent of mean volume across years, with roe deer as the staple and wild boar as the secondary prey. In the Plain, the hierarchy was inverted: medium-sized mammals made up 51 to 88 percent of the diet, and a single species, the coypu, accounted for the bulk of it, ranging from 83.3 percent of consumed volume in 2021 to 43.1 percent in 2025. Wild ungulates in the Plain rose from under 10 percent in 2021 to 42.6 percent in 2025, driven mainly by increasing consumption of roe deer. A two-way permutational multivariate analysis of variance confirmed that sector alone explained 48 percent of the variation in diet composition, a highly significant effect, and that the sector-by-year interaction was also significant, meaning the gap between the two populations narrowed as colonization proceeded.

A similarity percentage analysis pinpointed just two species as the engines of dietary divergence between the mountains and the plain. Coypu alone accounted for 38.5 percent of the dissimilarity, and together with roe deer the pair explained 71.6 percent of the total. Generalized linear models of prey occurrence revealed mirror-image trajectories: coypu occurrence increased over time in the Apennines while declining in the Plain, whereas roe deer occurrence decreased in the Apennines and climbed steadily in the Plain. By 2025 the two sectors’ diets were no longer statistically distinguishable, suggesting a progressive dietary adjustment as the lowland packs matured.

The coypu’s rise to keystone status in the wolves’ lowland menu makes ecological sense on several counts. The rodent, introduced to Italy through escapes and releases from fur farms, is extremely abundant and widespread in lowland waterways, relatively easy to capture, and at a typical body mass of 4 to 8 kilograms delivers a substantial energetic reward while being far easier to subdue than an ungulate. The authors also suggest that, as an invasive species with no evolutionary history alongside wolves, the coypu probably retains weak antipredator responses. In this light, the coypu functions as an ecological subsidy that may have facilitated wolf persistence and pack establishment during the vulnerable early phase of colonization, and future work will explore whether wolf predation measurably suppresses coypu populations and reduces the damage this invasive species inflicts on agriculture and wetland ecosystems.

The Apennine data added an unexpected twist of its own: a pronounced temporal switch between roe deer and wild boar. Wild boar consumption surged from 14.3 percent of diet volume in 2021 to a peak of 47.5 percent in 2023 before collapsing to 5.7 percent in 2025, while roe deer followed the opposite curve, dipping to 38.3 percent in 2023 and rebounding to 69.3 percent by 2025. The authors propose a plausible driver: the spread of African swine fever across northern Italy. Infected wild boar can show disorientation, abnormal movements, reduced wariness, and weakened condition, making them easier prey, so wolves may have temporarily cashed in on a pool of vulnerable individuals before shifting back to their traditional reliance on roe deer as the susceptible animals dwindled.

Trophic niche breadth, measured with the standardized Levins index, stayed narrow in both sectors, confirming that even in a novel landscape the wolves remained specialized rather than generalist foragers. Yet the trajectory differed: niche breadth in the Apennines hovered between 0.01 and 0.06 with overlapping confidence intervals throughout, while in the Plain it climbed from 0.04 in 2021 to 0.18 in 2025, the only year showing clear separation between sectors. The authors interpret this broadening as evidence of progressive dietary adjustment: newly established packs initially exploit the most accessible prey, then, as packs grow and their energetic demands rise with reproduction, larger prey such as roe deer become more profitable because each successful hunt yields far more biomass.

Taken together, the results reframe what wolf recovery in human-dominated Europe actually looks like on the ground. The predators did not need garbage, livestock, or pets to conquer the Po Plain; they needed a river corridor, relict woodland, dense roe deer populations, and a plump invasive rodent. The study also carries practical implications for coexistence: if lowland wolves can sustain themselves almost entirely on wild and invasive prey, conflict with farmers may remain limited, and coypu control might even find an unexpected ally. As wolf populations continue to expand across the continent’s agricultural heartlands, the Italian case suggests that their diets, like their ranges, are dynamic, shifting from whatever is easiest to catch during initial settlement toward the larger prey that sustain long-term persistence.

Subject of Research: Dietary adaptation of recolonizing gray wolves in historical Apennine range versus the human-dominated Po Plain of northern Italy

Article Title: Comparing wolf feeding ecology between historical ranges and recently colonized human-dominated lowlands

Article References: Torretta, E., Giussani, L., Rampazi, G., Dondina, O., Di Francesco, M., Canova, L., & von Hardenberg, A. (2026). Comparing wolf feeding ecology between historical ranges and recently colonized human-dominated lowlands. Frontiers in Ethology, 5, Article 1950752. https://doi.org/10.3389/fetho.2026.1950752

Image Credits: AI Generated

DOI: 10.3389/fetho.2026.1950752

Keywords: gray wolf, Canis lupus, wolf diet, coypu, Po Plain, Apennines, trophic niche breadth, scat analysis, invasive species, human-dominated landscapes, roe deer, wild boar