Carcass Consumption Research Articles

Lions Panthera leo Prefer Killing Certain Cattle Bos taurus Types.

Simple SummaryLivestock production continues to increase throughout the world. Meanwhile, lions are becoming increasingly endangered, in part due to the severe conflict arising from cattle predation. Because cattle closely resemble the body size, shape and herding patterns of wild lion prey, it becomes imperative to understand lion preferences for specific cattle to enhance our ability to design appropriate predation mitigation measures, reduce conflict, and ultimately improve the conservation of lions. Investigating cattle predation patterns in Botswana’s Okavango Delta, we found that lions mostly killed cattle at night and targeted the easiest prey, such as cattle without horns. However, lion preferences differed according to hunting circumstances. Where cattle were confined in enclosures, lions preferred young inexperienced calves, often leading to considerable losses in a single incident. When cattle were left out grazing unprotected, lions preferentially killed cattle with mixed coat patterns and lone males. Losses to lions were driven by cattle characteristics associated with easy husbandry, resulting from domestication. Widespread cattle availability and cavalier protection efforts further fuel losses because cattle no longer possess the key features that enabled their ancestors to coexist with large predators. Cattle are now reliant upon humans to perform critical protection activities.Lion predation on cattle causes severe human–wildlife conflict that results in retaliatory persecution throughout the lion’s geographic range. Cattle closely resemble the body size, shape, and herding patterns of preferred lion prey species. We studied cattle depredation patterns in Botswana’s Okavango Delta and tested whether lions exhibited specific preferences based on cattle demographic characteristics (sex and age), as well as morphological traits (body mass, horn length, and pelage patterns). We also tested whether human disturbance of kills influenced lion energy intake and whether depredation circumstances influenced loss levels. Lions predominantly killed cattle at night (87.1%) and exhibited no preference for either sex. Overall, bulls and calves were most preferred, whereas heifers were significantly avoided, as were cattle with uniform colour patterns. Cattle with mottled pelage patterns were most preferred, especially among free-roaming herds. Preferences were context-specific, with lions preferring inexperienced calves during enclosure attacks (including multiple cases of surplus killing) and free-roaming bulls and oxen. About 13% of adult cattle had no horns, and these were preferentially targeted by lions, while cattle with short horns were killed in accordance with their availability and long horned cattle were highly avoided. The contemporary morphology of Tswana cattle that resulted from unnatural selective pressures during domestication does not offer effective antipredatory protection. Human disturbance of feeding soon after kills occurred reduced cattle carcass consumption by >40% (or about 30 kg per carcass per lion). Lions killed significantly more cattle in nonfortified enclosures than in the veldt, although this was influenced by surplus killing. Our results suggest that cattle predation by lions is driven by availability and cavalier husbandry practices, coupled with morphological features associated with facilitating easy husbandry. Cattle no longer exhibit the key features that enabled their ancestors to coexist with large predators and are now reliant upon humans to perform critical antipredator activities. Hence, the responsibility for mitigating human–wildlife conflict involving lions and cattle lies with people in either breeding traits that minimise predation or adequately protecting their cattle.

Vertebrate Scavengers Control Abundance of Diarrhea-causing Bacteria in Tropical Plantations.

Scavenging is a common phenomenon, particularly amongst carnivorous vertebrates. By consuming carrion, vertebrate scavengers reduce resource availability for both pathogenic bacteria and their insect vectors. We investigated the ability of wild vertebrate scavengers to control agents of human diarrheal diseases (specifically Salmonella spp. and Shiga toxin-producing Escherichia coli [STEC]) in oil palm plantations in Sabah (East Malaysia), and the existence of spillover effect whereby additional vertebrate scavengers from adjacent forest patches result in greater disease control in plantation sections near these forest edges. Experimental carcasses were removed by common scavengers (Varanus salvator, Canis lupus familiaris, and Viverra tangalunga) at different time points, and this determined the length of time that the carcasses persisted in the environment. The amount of pathogenic bacteria on the surfaces of filth flies collected above the experimental carcasses was positively correlated to the duration of carcass persistence, and reduction in pathogenic bacterial abundances was largely due to carcass consumption by these vertebrate scavengers. Instead of a predicted positive spillover effect (greater scavenger activity near forest edges, hence reduced pathogen abundance), we detected a weak inverse spillover effect in which STEC counts were marginally higher in plantation sections near forest patches, and human hunting along the forest-plantation boundaries could explain this. We propose that making oil palm plantations scavenger-friendly could yield great human health benefits for the millions of workers employed in this rapidly-expanding industry, without drastically changing current management practices.

Rewilding traditional grazing areas affects scavenger assemblages and carcass consumption patterns

The abandonment of traditional livestock farming systems in Mediterranean countries is triggering a large-scale habitat transformation, which, in general, consists of the replacement of open grazing areas by woodlands through non-managed regeneration. As a consequence, wild ungulates are occupying rapidly the empty niche left by domestic ungulates. Both types of ungulates represent the main trophic resource for large vertebrate scavengers. However, a comparison of how vertebrate scavengers consume ungulate carcasses in different habitats with different ungulate species composition is lacking. This knowledge is essential to forecast the possible consequences of the current farmland abandonment on scavenger species. Here, we compared the scavenging patterns of 24 wild and 24 domestic ungulate carcasses in a mountainous region of southern Spain monitored through camera trapping. Our results show that carcasses of domestic ungulates, which concentrate in large numbers in open pasturelands, were detected and consumed earlier than those of wild ungulate carcasses, which frequently occur in much lower densities at more heterogenous habitats such as shrublands and forest. Richness and abundance of scavengers were also higher at domestic ungulate carcasses in open habitats. Vultures, mainly griffons (Gyps fulvus), consumed most of the carcasses, although mammalian facultative scavengers, mainly wild boar (Sus scrofa) and red fox (Vulpes vulpes), also contributed importantly to the consumption of wild ungulate carcasses in areas with higher vegetation cover. Our findings evidence that the abandonment of traditional grazing may entail consequences for the scavenger community, which should be considered by ecologists and wildlife managers.

Avoidance of carnivore carcasses by vertebrate scavengers enables colonization by a diverse community of carrion insects.

Carrion resources sustain a complex and diverse community of both vertebrate and invertebrate scavengers, either obligate or facultative. However, although carrion ecology has received increasing scientific attention in recent years, our understanding of carrion partitioning in natural conditions is severely limited as most studies are restricted either to the vertebrate or the insect scavenger communities. Moreover, carnivore carcasses have been traditionally neglected as study model. Here, we provide the first data on the partitioning between vertebrate and invertebrate scavengers of medium-sized carnivore carcasses, red fox (Vulpes vulpes (Linnaeus)), in two mountainous Mediterranean areas of south-eastern Spain. Carcasses were visited by several mammalian and avian scavengers, but only one carcass was partially consumed by golden eagle Aquila chrysaetos (Linnaeus). These results provide additional support to the carnivore carrion-avoidance hypothesis, which suggests that mammalian carnivores avoid the consumption of carnivore carcasses to prevent disease transmission risk. In turn, the absence of vertebrate scavengers at carnivore carcasses enabled a diverse and well-structured successional community of insects to colonise the carcasses. The observed richness and abundance of the most frequent families was more influenced by the decomposition time than by the study area. Overall, our study encourages further research on carrion resource partitioning in natural conditions.

Long-term wildlife mortality surveillance in northern Congo: a model for the detection of Ebola virus disease epizootics.

Ebolavirus (EBOV) has caused disease outbreaks taking thousands of lives, costing billions of dollars in control efforts and threatening great ape populations. EBOV ecology is not fully understood but infected wildlife and consumption of animal carcasses have been linked to human outbreaks, especially in the Congo Basin. Partnering with the Congolese Ministry of Health, we conducted wildlife mortality surveillance and educational outreach in the northern Republic of Congo (RoC). Designed for EBOV detection and to alert public health authorities, we established a low-cost wildlife mortality reporting network covering 50 000 km2. Simultaneously, we delivered educational outreach promoting behavioural change to over 6600 people in rural northern RoC. We achieved specimen collection by training project staff on a safe sampling protocol and equipping geographically distributed bases with sampling kits. We established in-country diagnostics for EBOV testing, reducing diagnostic turnaround time to 3 days and demonstrated the absence of EBOV in 58 carcasses. Central Africa remains a high-risk EBOV region, but RoC, home to the largest remaining populations of great apes, has not had an epidemic since 2005. This effort continues to function as an untested early warning system in RoC, where people and great apes have died from past Ebola virus disease outbreaks. This article is part of the theme issue 'Dynamic and integrative approaches to understanding pathogen spillover'.

Survival profiles from linear models versus Weibull models: Estimating stable and stationary population structures for Pleistocene large mammals

Survival and mortality profiles of mammalian species can provide information on the environmental context of Pleistocene archaeopaleontological localities as well as on the agents involved in the site formation process (e.g., the role played by the bone-accumulating agents, including their patterns of food procurement and carcass consumption, or the strategies of space use by carnivores and humans). Environmental context (i.e., climate and vegetation cover) and meat availability were both relevant factors for determining human settlements in Europe during the Pleistocene. For this reason, to gain deeper insights on the paleoecology of the large mammal communities can provide key information on human evolution and dispersal patterns. In this study we compare two mathematical approaches that allow reconstructing survival and mortality profiles of large mammals and their age-structured populations: the linear model and the Weibull model. Both approaches provide similar results for all species of large mammals analyzed. The lowest correlation coefficient was for Bison bison (0.789), but the difference in biomass estimates between the models decreases to <2%. When both methodologies were compared at the community level in the Orce sites, the ecological indexes used to compare paleocommunities showed also differences of <2%. Given the similarities in the output data derived from both models, we suggest a preferential use of the Weibull model due to its strength of results and easier computation compared to the linear model. Moreover, α and β parameters of the Weibull model supply information on the fertility and maturity of the age-structured populations, which are useful for differentiating among the reproductive strategies of the species compared. Therefore, our results suggest that the Weibull model is a valuable tool for investigating the availability of meat resources and the level of competition among carnivores in the Pleistocene communities of large mammals that inhabited Europe during the Pleistocene.

Very human bears: Wild brown bear neo-taphonomic signature and its equifinality problems in archaeological contexts

Different agents can lead to similar damage patterns, and different causes can result in the same type of modification. This phenomenon was defined by Lyman (1987) as a problem of equifinality, with which the researcher warned about the risks of making direct systematic correlations. The fact that a specific type of damage cannot be linked to a single actor, behaviour or ecological context is primarily applicable to damage associated with the direct consumption of carcasses. Some carnivores show physical and dental characteristics that could lead to bone modifications potentially like those generated by humans. For example, bears have a bunodont dentition and plantigrade locomotion –the latter allows them to frequently release and use their claws as “hands”. Here, we present the neo-taphonomical study of 17 ungulate carcasses eaten by wild brown bears (Ursus arctos arctos) in the Spanish Pyrenees. Our observations express this equifinal problem due to the similarities between tooth marks and peeling generated by both bears and humans. This fact is especially significant, given that peeling and the combination of this damage with visible tooth marks were primarily associated with the feeding activities of humans and chimpanzees (Pan troglodytes) and only anecdotally with other taphonomic agents, such as spotted hyenas. With this research, we try to show some equifinal phenomena that could occur in Pleistocene faunal assemblages as well, where the presence of both hominids and bears is documented.

Impact of Northern Hemisphere daylight hours on unsupplemented vitamin D and E concentrations in horses on pasture in Michigan

The metacestode stage of the tapeworm, Taenia ovis, causes cystic lesions in the skeletal and cardiac muscle of sheep, which can result in the condemnation of the entire carcass. In recent years, Canadian farms have seen a marked increase in the number of condemnations due to T. ovis. Mathematical transmission models provide a useful tool for predicting parasite transmission and for evaluating the efficacy of potential control options. To date, no model has been developed exclusively for T. ovis. In the work described here, a compartmental, deterministic transmission model was developed to better understand the transmission dynamics of T. ovis on Canadian sheep farms. The model was intended to be practical, and represent the transmission of infection burdens in lambs that result in carcass condemnation, or transmission to canids. All transmission parameters were obtained from the literature or, when unavailable, expert opinion. The model incorporated each stage of the parasite lifecycle using the most probable transmission route on Canadian sheep farms; including definitive host (guard dogs), intermediate host (pastured lambs), and environment. Based on literature, the model performed as expected, and provided a reasonable estimate of parasite prevalence in lambs. In addition, modeling allowed the efficacy of potential control options to be evaluated and compared. Model simulations suggested that infection risk in market lambs could be eliminated through the regular treatment of guardian dogs every fifth week with an appropriate cestocide, or through eliminating carcass consumption by guardian dogs.

Don't cry over spilled ink: Missing context prevents replication and creates the Rorschach effect in bone surface modification studies

The scientific replicability crisis has recently focused on bone surface modification (BSM) analysis, which underlies zooarchaeological and anthropological conclusions about the ecology and evolution of tool-assisted carcass consumption behavior. We review a recent blind test of inter-analyst correspondence in morphometric analysis of experimentally generated butchery marks that advocates algorithmic methods for diagnosing and measuring BSM in an effort to standardize methodology and minimize inter-analyst error (Domínguez-Rodrigo et al., 2017. Use and abuse of cut mark analyses: The Rorschach effect. Journal of Archaeological Science, 86, 14–23. https://doi.org/10.1016/j.jas.2017.08.001). This study overstates concern about the inaccuracy of BSM measurement and interpretation, concluding that BSM analysis is a subjective, non-scientific endeavor. Based on a minimally described sample of cut marks, it measures variables that involve inherent inaccuracy and subjectivity and overlooks how the contexts of experimental sample generation – particularly the difference between immanent and configurational processes – differentially affect cut mark morphometrics. We illustrate this discussion with experimental taphonomic examples focused on analytical context including sample construction and control over factors that affect cut mark cross-sectional size. Our analysis suggests the relationship between tool attributes and cut mark morphology is not generalizable to all experimental and archaeological butchery contexts. We show that our experimental samples capture metric variability observed in archaeological cut marks, but that intentionally incised marks and realistic defleshing marks differ in width and depth. Further, when controlling for factors that impact cut mark size including animal size class, tool type, butcher experience, and density across bone portions, overlapping cut mark widths and depths produced by phonolite and ignimbrite flakes lead to poor classification of marks according to causal flake material, which casts doubt on the ability to discriminate cut marks made by different materials. We build datasets that include diverse experimental contexts and suggest that meta-analysis can disentangle how multiple configurational factors contribute to cut mark morphometric attributes. Ultimately, progress in BSM analysis rests on inter-analyst replicability, which must be preceded by clear discussion of all parts of the inferential loop – from the design of experiments that generate actualistic analogues, to their use in supporting archaeological arguments. Otherwise, problematic expert knowledge traditions may mask arguments from authority in sophisticated methodological language and under-reported experimental context.

The impact of flake tool attributes and butcher experience on carcass processing time and efficiency during experimental butchery trials

AbstractButchery involves using tools to process animal carcasses during consumption of tissue packages, and this technological adaptation has a deep connection with evolving human dietary ecology. Studying butchery informs archaeological inferences about lithic artefact function and site formation and describes skeletal traces of carcass consumption, which may corroborate the butchery function of certain tools. Diverse methodologies including subjective personal observations and well‐controlled experiments that investigate abstracted slicing mechanics or realistic butchery scenarios provide mixed conclusions about which kinds of tools are more efficient for butchery and whether their archaeological traces can be discriminated. Much less analytical attention is devoted to investigating whether a butcher's experience using stone tools to process carcasses impacts their performance, which may confound experimental assessment of how tool attributes are related to butchery efficiency. These experiments examine butchery performance in two novices over 40 goat forelimb and hindlimb trials where a single flake was used to deflesh and disarticulate a limb. By measuring butchery performance as defleshing efficiency (the amount of meat removed per second) and the time necessary to disarticulate limb elements, we demonstrate that in general, both butchers performed similarly when butchering forelimbs and hindlimbs and did not exhibit a strong learning curve of performance improvement. As well, flake weight, size, and cutting edge length were positively related to defleshing efficiency and negatively related to disarticulation time, suggesting that larger flakes are better butchery tools. Our results suggest that anatomical differences between forelimbs and hindlimbs did not impact butchery timing or efficiency and butchery performance is similar across novices. To maximize comparability of experimental butchery results, we encourage future research to examine butchery performance with respect to animal or tissue package size and investigate how butcher experience impacts performance.

Winter Scavenging of Ungulate Carrion By Bald Eagles, Common Ravens, and Coyotes In Northern Arizona

Ungulate carrion supports an unusual canine-corvid-eagle winter scavenging guild in northern Arizona. To evaluate the effect of location and habitat on carcass use and longevity, between December 1996 and April 2008 we recorded 870 observations of Bald Eagles (Haliaeetus leucocephalus), Common Ravens (Corvus corax) and coyotes (Canis latrans) scavenging 123 ungulate carcasses: 103 elk (Cervus canadensis), 12 mule deer (Odocoileus hemionus), seven pronghorn antelope (Antilocapra americana), and one domestic cow (Bos taurus). Our temporal metric for measuring carcass longevity and scavenger presence was carcass-day (CD), numbered consecutively from the first day a carcass was recorded until it was consumed. We observed 38 separate carcasses (individual placement), 39 carcasses as part of three-carcass arrays in habitat associated with open, edge, and forest cover types (simultaneous choice), 22 carcasses left along the roadway where killed (monitored in place), and 24 carcasses partially skinned and/or cut open (facilitated). Elk carcasses lasted a mean 11.9 d (range 3–41), with 60% consumed during the first wk. Deer and pronghorn lasted 5.5 d (range 3–12) and 3.0 d (range 2–4), respectively. Ravens normally arrived by CD 3, Bald Eagles by CD 4, and coyotes by CD 6. Bald Eagles relied on ravens for discovery and sentinel duties, whereas both species depended on coyotes for accessibility. Winter- and road-killed carrion, not canine predation, drove carcass availability. Bald Eagles and coyotes used natural carrion more than human-influenced (road-killed or cut-open) carcasses, whereas Common Ravens were uninhibited by the latter. Removing ungulate carcasses from highway rights-of-way and partially opening them will promote quicker carcass consumption and safer avian scavenging by reducing potential for collisions with passing vehicles. A better understanding of the use of road-killed, large ungulate carrion may facilitate managing this supplemental food source as potential mitigation for other anthropogenic threats to both Bald and Golden Eagles (Aquila chrysaetos), including wind-energy development.

Top carnivore decline has cascading effects on scavengers and carrion persistence.

Top carnivores have suffered widespread global declines, with well-documented effects on mesopredators and herbivores. We know less about how carnivores affect ecosystems through scavenging. Tasmania's top carnivore, the Tasmanian devil (Sarcophilus harrisii), has suffered severe disease-induced population declines, providing a natural experiment on the role of scavenging in structuring communities. Using remote cameras and experimentally placed carcasses, we show that mesopredators consume more carrion in areas where devils have declined. Carcass consumption by the two native mesopredators was best predicted by competition for carrion, whereas consumption by the invasive mesopredator, the feral cat (Felis catus), was better predicted by the landscape-level abundance of devils, suggesting a relaxed landscape of fear where devils are suppressed. Reduced discovery of carcasses by devils was balanced by the increased discovery by mesopredators. Nonetheless, carcasses persisted approximately 2.6-fold longer where devils have declined, highlighting their importance for rapid carrion removal. The major beneficiary of increased carrion availability was the forest raven (Corvus tasmanicus). Population trends of ravens increased 2.2-fold from 1998 to 2017, the period of devil decline, but this increase occurred Tasmania-wide, making the cause unclear. This case study provides a little-studied potential mechanism for mesopredator release, with broad relevance to the vast areas of the world that have suffered carnivore declines.

Foraging traits of native predators determine their vulnerability to a toxic alien prey

Abstract Vulnerability to toxic alien prey varies among native predator species, depending on their toxin resistance. Although foraging traits relating to the intake of prey are also likely to influence predator vulnerability to toxic alien prey, these traits have received little attention. To address this issue, we studied the toxic impacts of an alien prey species (Bufo japonicus formosus toad hatchlings) on a carnivorous and an omnivorous native amphibian species (Hynobius retardatus salamander larvae and Rana pirica frog tadpoles, respectively) that both feed on alien B. japonicus formosus toad hatchlings. First, we designed a mesocosm and an aquarium experiment to evaluate the impact of B. japonicus formosus on the survival of native amphibians under various alien prey densities and predation regimes. Second, we performed several additional laboratory experiments to clarify specific processes of native amphibian mortality in the presence of the alien B. japonicus formosus toad hatchlings. We found that both native amphibian species were impacted by the alien B. japonicus formosus toad hatchlings. Interestingly, R. pirica frog tadpoles were more affected than H. retardatus salamander larvae, partly due to their lower toxin resistance and their higher toad consumption rate. Most importantly, omnivorous foraging traits (i.e., food sharing and carcass consumption) demonstrated by R. pirica frog tadpoles, but not by the strictly carnivorous H. retardatus salamander larvae, rendered the former particularly vulnerable to the toxic B. japonicus formosus toad hatchlings. This is the first study suggesting that species‐specific foraging traits such as food‐sharing and carcass consumption can determine predator vulnerability to toxic alien prey. This study emphasises the importance of investigating a wider array of predator traits as factors that determine their vulnerability to toxic alien prey. By doing so, we can understand what types of native species are strongly impacted by toxic alien prey and predict the ecological consequences of toxic species invasion.

A multidecade experiment shows that fertilization by salmon carcasses enhanced tree growth in the riparian zone.

As they return to spawn and die in their natal streams, anadromous, semelparous fishes such as Pacific salmon import marine-derived nutrients to otherwise nutrient-poor freshwater and riparian ecosystems. Diverse organisms exploit this resource, and previous studies have indicated that riparian tree growth may be enhanced by such marine-derived nutrients. However, these studies were largely inferential and did not account for all factors affecting tree growth. As an experimental test of the contribution of carcasses to tree growth, for 20yr, we systematically deposited all sockeye salmon (Oncorhynchus nerka) carcasses (217,055 individual salmon) in the riparian zone on one bank of a 2-km-long stream in southwestern Alaska, reducing carcass accumulation on one bank and enhancing it on the other. After accounting for partial consumption and movement of carcasses by brown bears (Ursus arctos) and variation in salmon abundance and body size, we estimated that 267,620kg of salmon were deposited on the enhanced bank and 45,200kg on the depleted bank over the 20yr, for a 5.9-fold difference in total mass. In 2016, we sampled needles of 84 white spruce trees (Picea glauca) the dominant riparian tree species, for foliar nitrogen (N) content and stable isotope ratios (δ15 N), and took core samples for annual growth increments. Stable isotope analysis indicated that marine-derived N was incorporated into the new growth of the trees on the enhanced bank. Analysis of tree cores indicated that in the two decades prior to our enhancement experiment, trees on the south-facing (subsequently the depleted) bank grew faster than those on the north-facing (later enhanced) bank. This difference was reduced significantly during the two decades of fertilization, indicating an effect of the carcass transfer experiment against the background of other factors affecting tree growth.

Using a dynamic bioenergetics-bioaccumulation model to understand mechanisms of uptake and bioaccumulation of salmon-derived contaminants by stream-resident fish

Ecosystem linkages created by migratory organisms such as Pacific salmon (Oncorhynchus spp.) facilitate the transfer of ecologically beneficial resource subsidies and environmentally damaging contaminants to recipient food webs. In the Laurentian Great Lakes, introduced Pacific salmon accumulate large contaminant burdens that they disperse to streams during spawning in the form of carcass and gametic tissue, with uncertain consequences for stream food webs. Here, we describe a coupled bioenergetics-bioaccumulation model parameterized using empirical and literature-sourced data to predict the dual effect of Pacific salmon on stream-resident brook trout (Salvelinus fontinalis) growth and contaminant bioaccumulation. Within the model, we developed four unique scenarios to ascertain how the (1) trophic pathway to contamination, (2) level of salmon egg consumption, (3) intensity and duration of salmon exposure, and (4) age of first exposure to salmon, affected growth and contaminant bioaccumulation in brook trout. Our model demonstrated that salmon egg consumption increased brook trout growth and PCB bioaccumulation while reducing Hg tissue concentrations. Other trophic pathways, including direct carcass consumption and an indirect food web pathway, did not strongly influence growth or contaminant bioaccumulation. Our model also demonstrated that variation in the magnitude and temporal duration of salmon egg consumption mostly strongly influenced the growth and contaminant concentration of younger brook trout. Overall, our model highlighted that Pacific salmon transfer energy and contaminants but this balance is dictated by the food web pathway and plasticity in the diet of stream-resident fish. Our mechanistic, model-based evaluation of salmon contaminant biotransport can be extended to predict the impact of other migratory fishes on recipient food webs.

Predator size and prey size–gut capacity ratios determine kill frequency and carcass production in terrestrial carnivorous mammals

Carnivore kill frequency is a fundamental part of predator–prey interactions, which are important shapers of ecosystems. Current field kill frequency data are rare and existing models are insufficiently adapted to carnivore functional groups. We developed a kill frequency model accounting for carnivore mass, prey mass, pack size, partial consumption of prey and carnivore gut capacity. Two main carnivore functional groups, small prey‐feeders versus large prey‐feeders, were established based on the relationship between stomach capacity (C) and pack corrected prey mass (iMprey). Although the majority of small prey‐feeders is below, and of large prey‐feeders above a body mass of 10–20 kg, both occur across the whole body size spectrum, indicating that the dichotomy is rather linked to body size‐related ecology than physiology. The model predicts a negative relationship between predator size and kill frequency for large prey‐feeders. However, for small prey‐feeders, this negative relationship was absent. When comparing carnivore prey requirements to estimated stomach capacity, small carnivores may have to eat to their full capacity repeatedly per day, requiring fast digestion and gut clearance. Large carnivores do not necessarily have to eat to full gastric capacity per day, or do not need to eat every day, which in turn reduces kill frequencies or drives other ecological processes such as scavenging, kleptoparasitism, and partial carcass consumption. Where ecological conditions allow, large prey‐feeding appears attractive for carnivores, which can thus reduce activities related to hunting. This is particularly so for large carnivores, who can achieve distinct reductions in hunting activity due to their relatively large gut capacity.

Habitat characteristics from local to landscape scales combine to shape vertebrate scavenging communities

Abiotic and biotic factors modulate carcass consumption by scavengers, affecting ecosystem functioning. Habitat structure is arguably a key factor influencing scavenging, but its role remains poorly understood, particularly at small spatial scales. We examine how habitat characteristics at landscape (50–1000m radius) and local (≤10m radius) scales around carrion affect the structure of vertebrate scavenging communities. We used remote cameras to monitor the consumption of 151 ungulate carcasses in one temperate (55 carcasses) and two Mediterranean (56 and 40 carcasses) study areas in Spain in 2011–2013. Our results showed complex habitat–scavenger relationships that mainly relied upon the spatial scale, the type of carcass and the study area. While the response of scavenger richness to habitat characteristics was consistent across study areas, the effects of diversity varied regionally at the landscape scale. Large and medium-sized carcasses in open landscapes had lower scavenger richness, likely because open habitats promote vulture dominance. At the local scale, shrub cover lowered scavenger richness and diversity, hindering carrion location by avian scavengers. Our results suggest that the structure of vertebrate scavenging assemblages at carcasses is driven by carcass and habitat characteristics operating as ecological filters at different scales (i.e. local, landscape, and biogeographical), which affect a species’ ability to locate, access and dominate carrion. Understanding the factors underlying the complex habitat–community relationships shown here has implications for managing key ecosystem functions and services. We propose a multi-scale conceptual framework to disentangle scavenger–carcass relationships.

Identification and examination of inconspicuous carnivore modifications

Bone modifications are associated with a broad range of agents, including carnivores, stone tools, sediments, etc., and can be categorized as one of two types: conspicuous or inconspicuous. Contrary to the larger, more easily identifiable conspicuous modifications, inconspicuous modifications are small, shallow and almost unnoticeable without the aid of a hand lens and strong light, making them harder and more time consuming to identify. This has led to arguments for their omission from tooth mark counts, even though their presence on the bones of archaeological and paleontological faunal assemblages have been recognized and mentioned in literature as having interpretive potential.This study employs visible light microscopy and high resolution scanning electron microscopy to present evidence that positively identifies inconspicuous carnivore modifications as abrasions that also have diagnostic morphology which differentiates them from abrasion created by other taphonomic agents. These inconspicuous carnivore marks may also be associated with the presence of soft tissue and so may help reconstruct the amount of flesh present at specific stages of carcass consumption. This study shows the interpretive potential of ICA may be substantial, requiring their inclusion in tooth mark counts for more accurate reconstructions of past carnivore behavior.Furthermore, understanding the etiology and implications of inconspicuous carnivore marks may provide a new way to interpret faunal assemblages that exhibit such marks, such as those associated with FLK Zinjanthropus, Tanzania. Such interpretations may be able to help develop stronger inferences regarding methods of hominin carcass acquisition.

Exposure to whole chicken carcasses may present a greater risk of campylobacteriosis compared to exposure to chicken drumsticks.

In New Zealand, the major risk factor for campylobacteriosis has been identified as poultry consumption. New Zealanders consume different types of chicken meat which undergo different processing before entering the retail chain. The manipulations and jointing of chicken carcasses into pieces and the subsequent processing and packaging have the potential to cross-contaminate and reshuffle bacterial pathogens among the different products sold. The aim of this study was to analyse: (a) the differences in the viable count and population genetic structure between Campylobacter isolated from chicken drumsticks and whole carcass meat for retail sale over a 1-year period; and (b) the genetic relatedness of human and chicken isolates collected concurrently. Enumeration of Campylobacter was performed using a spiral plater combined with manual spread plating. Campylobacter isolates were identified by polymerase chain reaction and typed bymultilocus sequence typing (MLST). C.jejuni was the dominant species among both whole carcasses (63.5%) and drumsticks samples (73.8%), followed by C.coli (27% and 23.1%, respectively). After sample weight adjustment, whole carcasses showed significantly higher Campylobacter counts than drumsticks, with a significant difference in the counts between the commercial suppliers in both types of retail meat. MLST revealed 28 different sequence types among the two types of meat. Using permutational multivariate analysis of variance, statistically significant differences in the population genetic structures were observed between different suppliers but were not observed between the two types of chicken retail meat. In conclusion, we found differences in Campylobacter viable counts, suggesting consumption of whole carcasses may determine an exposure to a higher number of Campylobacter bacteria than consumption of chicken drumsticks. The Campylobacter population genetic structure did not differ between the two types of chicken retail meat. Therefore, source attribution studies based on MLST are unlikely to be biased by the selection of these types of retail meat during sampling.

FwJj70 – A potential Early Stone Age single carcass butchery locality preserved in a fragmentary surface assemblage

The Okote Member (1.39–1.53 million-years-ago) of the Koobi Fora Formation preserves a rich and well-resolved lithic archaeological record, but comparatively little is known about the paleoecology of stone tool use during hominins' carnivorous foraging behavior. Archaeological butchery traces are typically found in fragmentary assemblages with well-preserved cortical surfaces that include multiple butchered individuals and carcass parts, but conclusions about butchery behavior, including skeletal element profiles and element and individual estimates may be impacted by specimen identifiability and differential preservation during palimpsest assemblage formation. Here we present an analysis of a fragmentary surface assemblage of fossil bone, designated FwJj70, that includes butchered and tooth-marked specimens and fragments of additional mammal carcasses to explore the archaeological visibility of carcass consumption at the lower boundaries of data quality – in particular, imprecise specimen identifiability and poor assemblage preservation. FwJj70 includes a similar composition of mammalian families and size classes in comparison with the fauna recorded along 400 m of the same stratigraphic horizon but possesses less weathered specimens with fewer post-fossilization and dry fractures, suggesting that bone specimens were rapidly buried. Excavation in search of an in situ origin of the surface assemblage recovered three specimens, but did not reveal a clear archaeological horizon. FwJj70 includes 40 identifiable specimens from at least 21 elements and six mammalian individuals. Eight specimens from a minimum of four elements and a single individual preserve evidence of hominin butchery and may come from a single size-three mammal carcass. However, poor specimen identifiability and ex situ context lead to a coarse estimate of the true number of butchered animals in the assemblage, blurring the distinction between a single carcass butchery episode and consumption of multiple animals, and masking the activity of carnivores. Despite this equifinality, the anatomical location of butchery marks at FwJj70 provides evidence of discrete aspects of hominins' tool-assisted carnivorous foraging niche, including early access to limb flesh packages, bone marrow consumption, and competition with other carnivorous consumers.