Wolf Diet Research Articles

Natural pet food: a review of natural diets and their impact on canine and feline physiology.

The purpose of this review is to clarify the definition of "natural" as it pertains to commercial pet food and to summarize the scientific findings related to natural ingredients in pet foods and natural diets on the impact of pet health and physiology. The term "natural," when used to market commercial pet foods or pet food ingredients in the United States, has been defined by the Association of American Feed Control Officials and requires, at minimum, that the pet food be preserved with natural preservatives. However, pet owners may consider natural as something different than the regulatory definition. The natural pet food trend has focused on the inclusion of whole ingredients, including meats, fruits, and vegetables; avoiding ingredients perceived as heavily processed, including refined grains, fiber sources, and byproducts; and feeding according to ancestral or instinctual nutritional philosophies. Current scientific evidence supporting nutritional benefits of natural pet food products is limited to evaluations of dietary macronutrient profiles, fractionation of ingredients, and the processing of ingredients and final product. Domestic cats select a macronutrient profile (52% of ME from protein) similar to the diet of wild cats. Dogs have evolved much differently in their ability to metabolize carbohydrates and select a diet lower in protein (30% of ME from protein) than the diet of wild wolves. The inclusion of whole food ingredients in natural pet foods as opposed to fractionated ingredients may result in higher nutrient concentrations, including phytonutrients. Additionally, the processing of commercial pet food can impact digestibility, nutrient bioavailability, and safety, which are particularly important considerations with new product formats in the natural pet food category. Future opportunities exist to better understand the effect of natural diets on health and nutrition outcomes and to better integrate sustainable practices in the production of natural pet foods.

Linking Wolf Diet to Changes in Marine and Terrestrial Prey Abundance

Since most wolf (Canis lupus) diet studies have been conducted in inland ecosystems, comparatively few data are available on diets of wolves in coastal systems. We investigated the diet of wolves in Glacier Bay, Alaska, from 12 May to 28 June in both 2010 and 2011. Although we identified 12 different prey species, including birds and small to medium-sized mammals, in wolf scats, moose (Alces alces) was the most frequent food item, observed in 80% of all scats. In contrast, a study conducted in 1993 in an area 37 km away found harbor seal (Phoca vitulina richardii) in 41% of wolf scats. Although we cannot account for differences in sampling design between the two studies, wolf diets may have changed between the two time periods.

Anthropogenic effects on the feeding habits of wolves in an altered arid landscape of central Iran

We determined the diet of the poorly-studied Middle Eastern wolves (Canis lupus) in central Iran in 2009–2010. Food items consisted mainly of farmed chicken and domestic goat (i.e., anthropogenic resources) using both qualification and quantification methods. In contrast, we identified the remains of wild ungulates in negligible quantities. Our data simulations showed that poultry and goats are both primary food items of wolves in the study area. The relative importance of main prey items did not vary seasonally, and, although there were some minor differences in secondary food items, we did not reveal any seasonal effect in diet composition. The negligible consumption of wild prey strongly suggests that wolves are not, at present, a limiting factor for wild prey in our study area. Appropriate management of illegal dumping, in conjunction with excluding wolves and other carnivores from human refuse, would minimize the chance of human-carnivore encounters, wolf-livestock conflicts and, in turn, the persecution of carnivores. Our study contributed to our knowledge of the feeding ecology of the Middle Eastern wolves in areas with a relatively high abundance of anthropogenic foods and a moderately low abundance of wild prey.

Diets of sympatric red wolves and coyotes in northeastern North Carolina

Abstract The recent co-occurrence of red wolves (Canis rufus) and coyotes (Canis latrans) in eastern North Carolina provides a unique opportunity to study prey partitioning by sympatric canids. We collected scats from this region and examined them for prey contents. We used fecal DNA analysis to identify which taxa deposited each scat and multinomial modeling designed for mark–recapture data to investigate diets of sympatric red wolves and coyotes. Diets of red wolves and coyotes did not differ, but the proportion of small rodents in the composite scats of both canids was greater in the spring than in the summer. White-tailed deer (Odocoileus virginianus), rabbits (Sylvilagus spp.), and small rodents were the most common diet items in canid scats. The similarity of diet between red wolves and coyotes suggests that these 2 species may be affecting prey populations similarly.

Wolves, white‐tailed deer, and beaver: implications of seasonal prey switching for woodland caribou declines

Population increases of primary prey can negatively impact alternate prey populations via demographic and behavioural responses of a shared predator through apparent competition. Seasonal variation in prey selection patterns by predators also can affect secondary and incidental prey by reducing spatial separation. Global warming and landscape changes in Alberta's bitumen sands have resulted in prey enrichment, which is changing the large mammal predator–prey system and causing declines in woodland caribou Rangifer tarandus caribou populations. We assessed seasonal patterns of prey use and spatial selection by wolves Canis lupus in two woodland caribou ranges in northeastern Alberta, Canada, that have undergone prey enrichment following recent white‐tailed deer Odocoileus virginianus invasion. We determined whether risk of predation for caribou (incidental prey) and the proportion of wolf‐caused‐caribou mortalities varied with season. We found that wolves showed seasonal variation in primary prey use, with deer and beaver Castor canadensis being the most common prey items in wolf diet in winter and summer, respectively. These seasonal dietary patterns were reflected in seasonal wolf spatial resource selection and resulted in contrasting spatial relationships between wolves and caribou. During winter, wolf selection for areas used by deer maintained strong spatial separation between wolves and caribou, whereas wolf selection for areas used by beaver in summer increased the overlap with caribou. Changing patterns in wolf resource selection were reflected by caribou mortality patterns, with 76.2% of 42 adult female caribou mortalities occurring in summer. Understanding seasonal patterns of predation following prey enrichment in a multiprey system is essential when assessing the effect of predation on an incidental prey species. Our results support the conclusion that wolves are proximately responsible for woodland caribou population declines throughout much of their range.

Wolf diet and its impact on the ungulates community in a new recolonized area of Western Alps: Gran Paradiso National Park

The aim of this study is to evaluate how wolves affected the prey community in a newly recolonization area of the Western Alps, the Gran Paradiso National Park (GPNP). Since 1960's, this portion of the Alps hosts a multi-specific wild ungulate community. It lived in absence of large predators for more than a century. In 2006 a couple of wolves re-established in GPNP and in summer 2007 the first reproduction was documented. The present study was conducted during the following two years. In term of biomass consumed (Bio%), Alpine chamois was the main prey of wolves in all seasons (Bio%Summer 2007 = 70.13; Bio%Winter 2007/2008 = 56.99; Bio%Summer 2008 = 67.52; Bio%Winter 2008/2009 = 36.35), while roe deer were intensely consumed during the adverse season (Bio%W2007/2008 = 23.05 %; Bio%W2008/2009 = 42.47 %). Although cervids were much less abundant than bovids in the area, they represented one of the main food items of wolves, possibly because of the strong habitat overlap and altitude use between predator and preys. Moreover, the minor adaptation of cervids to the Alpine environment compared to bovids could affect their vulnerability and thus the respective consumption of the different species during the adverse season.

The genomic signature of dog domestication reveals adaptation to a starch-rich diet

The domestication of dogs was an important episode in the development of human civilization. The precise timing and location of this event is debated and little is known about the genetic changes that accompanied the transformation of ancient wolves into domestic dogs. Here we conduct whole-genome resequencing of dogs and wolves to identify 3.8 million genetic variants used to identify 36 genomic regions that probably represent targets for selection during dog domestication. Nineteen of these regions contain genes important in brain function, eight of which belong to nervous system development pathways and potentially underlie behavioural changes central to dog domestication. Ten genes with key roles in starch digestion and fat metabolism also show signals of selection. We identify candidate mutations in key genes and provide functional support for an increased starch digestion in dogs relative to wolves. Our results indicate that novel adaptations allowing the early ancestors of modern dogs to thrive on a diet rich in starch, relative to the carnivorous diet of wolves, constituted a crucial step in the early domestication of dogs.

Prey choice and diet of wolves related to ungulate communities and wolf subpopulations in Poland

Abstract Wolves (Canis lupus) belong to 3 genetically distinct subpopulations despite the absence of topographic barriers limiting dispersal. Based on data on wolf diets from 13 localities and wolf kill remains from a national-scale census, we investigated regional variation in wolf diet in relation to species structure of ungulate communities and spatial genetic differentiation of wolf populations. We also tested if various sources of data on wolf prey (scats and kills) and availability of ungulates (game inventory and harvest) yielded comparable results on prey selection. The main prey of wolves was red deer (Cervus elaphus), roe deer (Capreolus capreolus), and wild boar (Sus scrofa). The proportion of main prey in wolf diets increased with prey availability in the community, yet wolves selected red deer, preyed on roe deer proportionally to their relative abundance, and avoided wild boar. Large prey was recorded among kills more often than small prey. Despite similar species structure of ungulate commu...

Prey Selection by an Apex Predator: The Importance of Sampling Uncertainty

The impact of predation on prey populations has long been a focus of ecologists, but a firm understanding of the factors influencing prey selection, a key predictor of that impact, remains elusive. High levels of variability observed in prey selection may reflect true differences in the ecology of different communities but might also reflect a failure to deal adequately with uncertainties in the underlying data. Indeed, our review showed that less than 10% of studies of European wolf predation accounted for sampling uncertainty. Here, we relate annual variability in wolf diet to prey availability and examine temporal patterns in prey selection; in particular, we identify how considering uncertainty alters conclusions regarding prey selection.Over nine years, we collected 1,974 wolf scats and conducted drive censuses of ungulates in Alpe di Catenaia, Italy. We bootstrapped scat and census data within years to construct confidence intervals around estimates of prey use, availability and selection. Wolf diet was dominated by boar (61.5±3.90 [SE] % of biomass eaten) and roe deer (33.7±3.61%). Temporal patterns of prey densities revealed that the proportion of roe deer in wolf diet peaked when boar densities were low, not when roe deer densities were highest. Considering only the two dominant prey types, Manly's standardized selection index using all data across years indicated selection for boar (mean = 0.73±0.023). However, sampling error resulted in wide confidence intervals around estimates of prey selection. Thus, despite considerable variation in yearly estimates, confidence intervals for all years overlapped. Failing to consider such uncertainty could lead erroneously to the assumption of differences in prey selection among years. This study highlights the importance of considering temporal variation in relative prey availability and accounting for sampling uncertainty when interpreting the results of dietary studies.

Using Bayesian stable isotope mixing models to estimate wolf diet in a multi‐prey ecosystem

AbstractStable isotope analysis (SIA) of wolf (Canis lupus) tissues can be used to estimate diet and intra‐population diet variability when potential prey have distinct δ13C and δ15N values. We tested this technique using guard hairs collected from 44 wolves in 12 northwestern Montana packs, summer 2009. We used hierarchical Bayesian stable isotope mixing models to determine diet and scales of diet variation from δ13C and δ15N of wolves and potential prey, white‐tailed deer (Odocoileus virginianus), mule deer (Odocoileus hemionus), elk (Cervus canadensis), moose (Alces alces), snowshoe hare (Lepus americanus), and other prey. As a check on SIA results, we conducted a separate diet analysis with temporally matched scats (i.e., collected in summer 2008) from 4 of the same packs. Wolves were centered on the ungulate prey in the isotope mixing space. Both methods revealed differences among pack diets and that wolves may consume moose in greater proportions than predicted by available biomass. Stable isotope analysis, and scat results were not entirely concordant; assumptions related to tissues of use in SIA, hair growth period in wolves, and scat sampling may have contributed to a mismatch between methods. Incorrect fractionation values, insufficient separation of prey in the isotope mixing space, choice of prior information in the Bayesian mixing models, and unexplained factors may have distorted diet estimates. However, the consistently high proportion of moose in pack diets suggests that increased population monitoring would benefit management of moose and wolves. Our results also support suggestions of other researchers that species‐specific fractionation values should be used whenever possible, and that SIA may sometimes only provide indices of use for general groups of prey (e.g., large ungulates). © 2012 The Wildlife Society.

Wolf (Canis lupus) feeding habits during the first eight years of its occurrence in Germany

Due to the fact that the feeding habits of large carnivores are the main contentious point when they start resettling regions they were absent from for several decades, the diet composition of the wolves in Germany was analysed from the beginning of this process. Wolves in Germany primarily feed on wild ungulates, which make up more than 96% of their diet. The dominating prey species is the roe deer (55.3%), followed by red deer (20.8%) and wild boar (17.7%). The second important food category are the leporids (2.9% of Biomass), whereas livestock makes up only 0.6% of all biomass consumed. Wolves clearly prefer hunting on juvenile to adult red deer; roe deer are not selected after their age. We found seasonal differences in the diet composition with a higher amount of wild boar in spring and winter, when a high amount of juveniles and weakened animals, respectively, are available. In the first years of the study the percentage of red deer was much higher, and the percentage of roe deer therefore was lower than the following years. The amount of wild boar in the wolf diet fluctuated most in the first three years. Diet composition remained constant during the last five years. Wolves needed less than two generations for adapting to the new conditions in the cultivated landscape of eastern Germany.

Selection of wild ungulates by wolves Canis lupus (L. 1758) in an area of the Northern Apennines (North Italy)

We investigated the patterns of wild ungulate selection by wolves in an 860 km2 study area of the Northern Apennines (North Italy), in order to detect seasonal variation in wolf diet and changes of feeding habits in relation to the increased abundance of wild ungulates. From June 2007 to May 2008 we collected wolf scats and recorded the signs of presence of wild ungulate species along 25 transects, representative of the different habitat types within the study area. We analysed the scats to identify the main food items used by wolves in each season and we compared the proportions of biomass of wild ungulate species in the diet (use) to those calculated from the signs of presence (availability). We recorded significant seasonal changes in wolf feeding habits, but the main food items were wild ungulates, mainly wild boars, and medium-sized mammals. Livestock (sheep, goats, and calves) were used only in summer and early autumn, during the grazing period, in small quantities. Comparing the current diet of wolves to that recorded in the past in the same study area highlighted significant differences for wild ungulates and livestock, the former being more used nowadays and the latter less. Our study showed that, in the Northern Apennines, the feeding behaviour of wolves has evolved towards a greater use of wild prey, so reducing the impact on livestock and consequently wolf-human conflicts. Moreover, predation by wolves was directed towards the most abundant species of wild ungulates.

Food Habits of Red Wolves during Pup-Rearing Season

Abstract Canis rufus (Red Wolf) is critically endangered, with the only wild population consisting of <150 individuals. Currently, little is known about the food habits of this population. Such information may be vital to managing for the population's long-term persistence. We collected scats of Red Wolves for two consecutive pup-rearing seasons from six packs, classified contents into prey categories, and assessed diet composition for each pack. Five of the six packs studied consumed only mammalian prey items. Adult Odocoileus virginianus (White-tailed Deer) and White-tailed Deer fawns accounted for 37–66% of diet of Red Wolves depending on the metric of diet composition. Adult White-tailed Deer and White-tailed Deer fawns accounted for 21–83% of the diet of individual packs of Red Wolves according to biomass consumed. Two packs regularly consumed foods associated with humans. Generalized linear modeling indicated that diet varied between packs and was not influenced by reproductive status, nor did diet ...

Diet of wolves Canis lupus returning to Hungary

At the end of the nineteenth century, the wolf Canis lupus was extinct in Hungary and in recent decades has returned to the northern highland area of the country. The diet of wolves living in groups in Aggteleki National Park was investigated using scat analysis (n = 81 scats) and prey remains (n = 31 carcasses). Throughout the year wolves (average, minimum two wolves per year) consumed mostly wild-living ungulates (mean percent of biomass consumed, B% 97.2%; relative frequency of occurrence, %O 74.0%). The wild boar Sus scrofa was the most common prey item found in wolf scat (%B 35.6%) and is also the most commonly occurring ungulate in the study areas. The second most commonly occurring prey item in wolf scat was red deer Cervus elaphus (B% 32.8%). Conversely, prey remain analyses revealed wild boar as the second most commonly utilised prey species (%O 16.1%) after red deer (%O 67.7%). The roe deer Capreolus capreolus that occurs at lower population densities was the third most commonly utilised prey species. The importance of low population density mouflon Ovis aries, livestock and other food types was low. The results are similar to those found in the northern part of the Carpathian Mountains.

Diet and prey selection of wolves ( Canis lupus) recolonising Western and Central Poland

Wolf Canis lupus diet was studied by scat analysis in four main and several other locations recolonised by this species in Central and Western Poland between 2002 and 2009. Wild ungulates made up 94.8% of the total biomass of food consumed, with the most common being roe deer Capreolus capreolus (42.8%), wild boar Sus scrofa (22.6%) and red deer Cervus elaphus (22.2%). Supplementary prey were: fallow deer Dama dama (2.7%), brown hare Lepus europeus (2.5%) and Eurasian beaver Castor fiber (1.4%). Domestic animals, exclusively dogs and cats, made up 1.0% of food biomass. A high similarity in the ratio of wild ungulate species in wolf food biomass between study sites was observed. Wolves hunted wild ungulate species accordingly to their relative abundance in the community. As wild ungulates are abundant and livestock density is low the large forest tracts of Western Poland seems to be very good habitat for wolves. Therefore, with more dispersing wolves from Eastern Poland and Eastern Germany, wolf recovery could significantly accelerate in the next few years in this region.

Using stable isotopes to define diets of wolves in northern British Columbia, Canada

Wolves (Canis lupus), as both opportunistic and specialist predators, can limit and regulate ungulate dynamics. As part of understanding predator–prey interactions in the largely undisturbed system of the Besa-Prophet area in northern British Columbia, we used stable isotopes of carbon and nitrogen to infer seasonal diets of 5 wolf packs. We selected the hair, tissue, or blood sample of each prey species that could best index within-season diet composition. Seasonal isotopic differences for a given sample type were as much as 0.28% d 13 C and 0.97% d 15 N. The large biomass species of moose (Alces americanus) and elk (Cervus elaphus) dominated the diets of wolves, but caribou (Rangifer tarandus) and Stone’s sheep (Ovis dalli stonei) also were locally or seasonally important to some packs. Mean isotopic determinations of summer food habits were correlated positively (P , 0.001) with proportions of prey by species determined from scat samples. This general agreement lends support for the tissue to diet discrimination values used in the Bayesian modeling and indicates that the longer-term dietary estimates from stable isotopes were reflective of shorter-term recent ingestion. Although moose have been assumed to be the most important prey item for wolves throughout the year in northern British Columbia, our results indicate that dietary dynamics of wolves in the Besa-Prophet area are more complex than previously reported.

From venison to beef: seasonal changes in wolf diet composition in a livestock grazing landscape

Wild ungulates are the primary prey for wolves in North America, but livestock predation is a concern in areas where wolves and livestock overlap. Using clusters of global positioning system telemetry relocations and scat analysis, we investigated wolf diets year‐round in southwestern Alberta, where seasonal cattle grazing is the predominant land use and wolf–cattle conflicts have increased in recent years. Both methods indicated a seasonal shift in wolf diets, from wild prey during the non‐grazing season to cattle in the grazing season. Wolves scavenged more frequently during the non‐grazing season than during the grazing season; 85% of all scavenging events occurred at ranchers' boneyards (where livestock carcasses are dumped), where wolves fed on dead livestock. Cattle represent a higher proportion of wolf diets than previously thought; we recommend the sanitary disposal of dead livestock to prevent wolves from becoming accustomed to feeding on livestock, and the development of management plans aimed at reducing predation on cattle if humans and wolves are to coexist on landscapes that are dominated by livestock ranching.

Invading white‐tailed deer change wolf–caribou dynamics in northeastern Alberta

AbstractHuman‐caused habitat change has been implicated in current woodland caribou (Rangifer tarandus caribou) population declines across North America. Increased early seral habitat associated with industrial footprint can result in an increase in ungulate densities and subsequently those of their predator, wolves (Canis lupus). Higher wolf densities can result in increased encounters between wolves and caribou and consequently higher caribou mortality. We contrasted changes in moose (Alces alces) and deer (Odocoileusspp.) densities and assessed their effects on wolf–caribou dynamics in northeastern Alberta, Canada, pre (1994–1997) versus post (2005–2009) major industrial expansion in the region. Observable white‐tailed deer (O. virginianus) increased 17.5‐fold but moose remained unchanged. Wolf numbers also increased from approximately 6–11.5/1,000 km2. Coincident with these changes, spatial overlap between wolf pack territories and caribou range was high relative to the mid‐1990s. The high number of wolf locations in caribou range suggests that forays were not merely exploratory, but rather represented hunting forays and denning locations. Scat analysis indicated that wolf consumption of moose declined substantively during this time period, whereas use of deer increased markedly and deer replaced moose as the primary prey of wolves. Caribou increased 10‐fold in the diet of wolves and caribou population trends in the region changed from stable to declining. Wolf use of beaver (Castor canadensis) increased since the mid‐1990s. We suggest that recent declines in woodland caribou populations in the southerly extent of their range have occurred because high deer densities resulted in a numeric response by wolves and consequently higher incidental predation on caribou. Our results indicate that management actions to conserve caribou must now include deer in primary prey and wolf reduction programs. © 2010 The Wildlife Society

Behavior of geladas and other endemic wildlife during a desert locust outbreak at Guassa, Ethiopia: ecological and conservation implications

Desert locust (Schistocerca gregaria) outbreaks have occurred repeatedly throughout recorded history in the Horn of Africa region, devastating crops and contributing to famines. In June 2009, a desert locust swarm invaded the Guassa Plateau, Ethiopia, a large and unusually intact Afroalpine tall-grass ecosystem, home to important populations of geladas (Theropithecus gelada), Ethiopian wolves (Canis simensis), thick-billed ravens (Corvus crassirostris), and other Ethiopian or Horn of Africa endemics. During the outbreak and its aftermath, we observed many animals, including geladas, ravens, and a wolf, feeding on locusts in large quantities. These observations suggest surprising flexibility in the normally highly specialized diets of geladas and wolves, including the potential for temporary but intensive insectivory during locust outbreaks. To our knowledge, Guassa is the highest elevation site (3,200-3,600 m) at which desert locusts, which require temperatures >20 degrees C for sustained flight, have been reported. Continued monitoring will be necessary to determine whether the June 2009 outbreak was an isolated incident or part of an emerging pattern in the Ethiopian Highlands linked to global warming. The intensive consumption of desert locusts by geladas, wolves, and ravens during the outbreak at Guassa raises concerns about pesticide-based locust control strategies and potential unintended adverse effects on endemic and endangered wildlife.

Diet of wolves Canis lupus recolonizing Switzerland : a preliminary approach

approach. - Dietary analyses were conducted using scat analysis and incidental carcass observations to investigate the diet of wolves returning to Switzerland. Red deer was the most frequent item eaten by wolves with 32.1% and 57.1% of frequency of occurrence in the scats and kills, respectively. Domestic ungulates accounted for 27.1% of the remains found in the scats. Kills were more frequent at lower altitude and at flatter locations than in randomly selected sites. Moreover, the slope of the latter was steeper than that of locations with kills. Wolf predation also occurred at closer distance to the nearest house and to the nearest roads than expected. Finally, gullies and ravines seemed to be a recurrent habitat feature for wolf kills.