Scavenging Events Research Articles

Carrion use by a reptile is influenced by season, habitat and competition with an apex mammalian scavenger.

Scavenging on carrion is critical and often fiercely competitive for a range of vertebrate species, from native apex predators to invasive species and even reptiles. Within Australia, a notable reptilian scavenger is the lace monitor (Varanus varius). In this study, we quantified lace monitor activity at carcasses and compared their use of the resource to common co-occurring predators that also scavenge; the invasive red fox (Vulpes vulpes) and a native apex predator, the dingo (Canis dingo). To do so, we deployed 80 macropod carcasses equally across seasons (summer and winter) and habitats (open and closed canopy) in a temperate bioregion and monitored vertebrate scavenging with camera traps. Lace monitor activity (visitation at carcass sites inclusive of both non-scavenging and scavenging events) was 1.67 times higher in summer than in winter, but it did not differ across closed and open habitats. Monitor activity occurred earlier after carcass deployment at sites deployed in summer than winter (1.47-fold earlier), and at carcasses in open than closed habitats (0.22-fold earlier). Lace monitors initially discovered carcass sites faster in summer than winter and before both red foxes and dingoes in summer. The species was active diurnally in both summer and winter, differing from the red fox, which was strictly a nocturnal scavenger and the dingo, which was significantly more active at night across both seasons. Finally, we found that lace monitor activity at carcass sites decreased slightly with higher rates of activity for dingoes (0.04-fold decrease as dingo activity increased), but not with red fox activity. Our results have implications for understanding lace monitor foraging and scavenging and highlight the value of monitoring carcasses to provide important insights into the behaviour of varanid lizards that scavenge.

Death at the water hole: Opportunistic hunting and scavenging events in the upper sequence of Middle Paleolithic Nesher Ramla, Israel

Distinguishing between selective and opportunistic hunting is a major challenge in Paleolithic archaeology, requiring the comparison of the human hunting record to the usually unknown natural prey abundance. Open-air hunting camps are ubiquitous in the Eurasian Middle Paleolithic (MP) record, alongside cave sites, and are often dominated by large-bodied species. In the Levant, MP faunal records differ between caves and open-air sites: Caves are dominated by mountain gazelle and fallow deer, while open-air sites are more aurochs-dominated. This discrepancy can be explained by transport patterns, but whether the abundance of aurochs in open-air sites is due to deliberate targeting or natural abundance in the landscape is unclear. The Nesher Ramla open-air site is a natural sinkhole in central Israel with an 8-m-deep MP sequence. Detailed zooarchaeological, dental wear, and isotope analyses of the upper sequence fauna found a highly diverse assemblage dominated by medium-sized ungulates in the uppermost phases (Units I and IIa). Results concerning ungulate dietary niches and isotopic signatures demonstrate that animals from different biomes and topographies congregated at the site. Evidence of human butchery is infrequent and fewer than carnivore modifications. Several articulated vertebral columns attest to in situ preservation. Our results demonstrate that the Nesher Ramla's uppermost sequence formed primarily under natural conditions, suggesting that it was a site of opportunistic hunting by humans and carnivores, probably targeting ungulates that came to the sinkhole to drink. Therefore, we consider this assemblage representative of the site's “natural” environment and use it as a benchmark for comparing assemblages and hunting strategies. Thus, we observe a clear difference between our case study and those recovered from the site's lower layers (Unit IIB and below) and other open-air sites. For the first time, we can show that the abundance of large bovines in MP open-air sites is not necessarily due to their abundance in the environment but to deliberate human planning and selective hunting.

Heterospecific visual cues and trophic facilitation processes used by a solitary bone‐eating vulture

AbstractWhile the influence of public information sharing on foraging strategies is of growing interest, empirical studies exploring intraguild social information use and facilitation roles between individuals with different trophic specializations remain scarce. Heterospecific facilitation should be more common in specialist foragers, for example, the bearded vulture Gypaetus barbatus, a solitary bone‐eating scavenger. We monitored 133 carcasses of different types/sizes in open and shrubland landscapes in the Spanish Pyrenees to explore bearded vulture foraging in relation to social information transfer and adaptive trophic behavior. We hypothesized that they might (1) feed on carcasses after initial heterospecific exploitation; (2) use heterospecifics to locate and/or exploit carcasses; and (3) prefer old carcasses over fresh ones. We recorded bearded vultures scavenging at 44 carcasses; 95.5% had been previously exploited by heterospecifics (93.2% by griffon vultures Gyps fulvus and 2.3% by golden eagles Aquila chrysaetos) while only two small‐sized carcasses were scavenged without previous heterospecific exploitation. Bearded vultures were not observed scavenging at carcasses used only by mammals. Both griffon and bearded vultures took longer to find carcasses in shrublands than in open landscapes. However, bearded vulture arrival times between landscapes after carcass discovery by griffon vultures were similar. Bearded vultures were more likely to discover a carcass the greater the number of griffon vultures exploiting it. Only 10.4% bearded vulture scavenging events occurred after the third week following heterospecific exploitation, suggesting that recently opened carcasses were preferred. Clearly, heterospecifics play an essential role in bearded vultures foraging success, and griffon vultures are fundamental facilitators for specialist foragers, both in providing visual cues to food location and in opening up carcasses to enable access to food.

Flooding, season and habitat interact to drive changes in vertebrate scavenging and carcass persistence rates

Scavenging dynamics are influenced by many abiotic and biotic factors, but there is little knowledge of how scavengers respond to extreme weather events. As carrion is a major driver of the organisation and structure of food webs within ecological communities, understanding the response of scavengers to extreme weather events is critical in a world that is increasingly subject to climate change. In this study, vertebrate scavenging and carcass persistence rates were quantified in the Simpson Desert of central Australia; a system that experiences major fluctuations and extremes in weather conditions. Specifically, a total of 80 adult red kangaroo (Osphranter rufus) carcasses were placed on the landscape and monitored using remote sensor cameras. This included 40 carcasses monitored before and then 40 carcasses monitored after a major flooding event. The carcasses were monitored equally before and after the flood across different seasons (warm and cool) and in dune and interdune habitats. Overall, a total of 8124 scavenging events for 97,976 visitation minutes were recorded for 11 vertebrate species within 30 days of carcass placement pre- and post-flood. Vertebrate scavenging increased post-flood in the warm season, especially by corvids which quadrupled their scavenging events during this time. There was little difference in carcass persistence between habitats, but carcasses persisted 5.3-fold longer post-flood in warm seasons despite increased vertebrate scavenging. The results demonstrate that a flood event can influence scavenging dynamics and suggest a need to further understand how seasons, habitats and extreme weather events can drive changes in carrion-based food webs.

Insights on the oldest terror bird (Aves, Phorusrhacidae) from the Eocene of Argentina

ABSTRACT Phorusrhacidae, commonly known as terror birds, constitutes a group of Cariamiformes that lived mainly in South America during the Cenozoic. The oldest record is represented by an isolated distal end of tibiotarsus (MLP-PV 75-II-3-22) discovered in the Lutetian (middle Eocene) levels of the Sarmiento Formation exposed in the Cañadón Vaca locality (Chubut Province, Argentina). Despite being frequently cited as the oldest specimen of Phorusrhacidae, this specimen has never been figured or comprehensively described. Motivated by this gap and recognising the significance of this finding, we conducted a detailed comparison of the tibiotarsus MLP-PV 75-II-3-22 with those of other species, assigning it to an indeterminate species of Psilopterinae with an estimated body mass of approximately 5 kg. Furthermore, following the identification of numerous tooth marks on the distal surface, we hypothesised that this small phorusrhacid may have been subjected to an attack or scavenging event by a small-to-medium predator, such as Nemolestes spalacotherinus, a hypercarnivorous marsupial previously recorded in the Cañadón Vaca assemblage.

Trophic interactions of sharks and crocodylians with a sea cow (Sirenia) from the Miocene of Venezuela

ABSTRACT Evidence of trophic interactions are not scarce in the fossil record, yet these are mostly represented by fragmentary fossils exhibiting marks of ambiguous significance. Differentiating between marks of active predation and scavenging events is therefore often challenging. Here, we report on a dugongine sea cow skeleton (partial skull and vertebrae) from the Lower to Middle Miocene Agua Clara Formation (Venezuela) with shark and crocodylian bite marks. The sirenian is identified as Culebratherium sp. and preserves crocodylian bite marks across the skeleton. The most conspicuous correspond to deep tooth impacts with dragging effect, concentrated in the rostrum of the specimen. We interpret these as the result of active predation because of the similarity with those produced when a crocodylian holds or rolls a prey. Additionally, shark bite marks can be observed throughout the skeleton, also evidenced by the finding of an isolated tiger shark (Galeocerdo aduncus) tooth associated with this skeleton. Because of the irregular distribution of the shark bite marks, these are interpreted as scavenging. Overall, these findings constitute one of the few records documenting multiple predators over a single prey, and as such provide a glimpse of the trophic networks during the Miocene in the region.

Effects of urbanization on the efficiency and composition of vertebrate scavengers

As human populations continue to expand, urbanization will increase and impact ecosystem processes, contribute to habitat fragmentation, and alter community composition of species. While some species can adapt to the rapidly changing environment, urbanization can favor generalist species and reshape food webs, which may result in ecological instability. Determining how wildlife respond to urbanization is necessary for management and city planning purposes in order to create suburban areas where humans and wildlife can coexist. One area that needs more focus is the effects of suburbanization on scavenging species, and how land development can alter scavenging dynamics and the redistribution of carrion-derived nutrients within food webs. We used motion activated cameras to monitor experimentally placed fish carcasses in riparian zones of suburban and rural areas in northeast Georgia, USA. We conducted 300 trials across both landscapes that were scavenged by 7 mammalian, 2 avian, and 2 reptilian species. Our results revealed fish carrion within riparian areas was readily consumed by terrestrial scavengers. However, carcass fate (whether the carcass was scavenged or not) and carcass persistence differed between suburban and rural landscapes. Carcasses were scavenged by vertebrates less often and persisted longer in rural landscapes. Species richness was similar and mesocarnivores were the predominant scavengers in both landscapes. However, scavenging by the Virginia opossum (Didelphis virginiana) was more prevalent in the suburban landscape relative to the rural landscape (61% and 36% of scavenging events, respectively). While raccoons (Procyon lotor) scavenged carcasses fairly equally across both landscapes, the American black bear (Ursus americanus) and red-shouldered hawk (Buteo lineatus) scavenged more frequently in rural areas. Our data suggest that suburban species, especially opossums, may be highly adapted to foraging in an anthropogenic environment. Additionally, nutrients from aquatic carcasses near water sources can readily move into terrestrial environments through scavenging. These results contribute to the growing body of scavenging ecology and the effects of urbanization on wildlife.

Observed trends in scavenging by common bottlenose dolphins (Tursiops truncatus truncatus) in for‐hire fisheries in the eastern U.S. Gulf of Mexico

AbstractInteractions between bottlenose dolphin and recreational rod and reel fisheries are a complex issue for resource managers in the United States, which may impact anglers' catch and lead to dangerous situations for scavenging or depredating dolphins. To examine this issue, we analyzed data collected by observers on for‐hire fishing vessels off the eastern U.S. Gulf Coast from 2009 to 2020. A generalized additive model indicated number of anglers, number of discarded fish, proximity to shore, prior scavenging events, type of released fish, and area fished were all significant predictors of scavenging by dolphins. The Florida panhandle had the highest odds of scavenging, while scavenging in the Big Bend and Tampa Bay has increased through time. The Florida panhandle is a well‐known area for illegal feeding of dolphins, suggesting human behavior may be influencing fisheries interactions. Model outputs indicate that dolphins are primarily cuing on fishing activity rather than number of discards, but are more likely to scavenge discards from the family Lutjanidae (snappers), which comprised 40% of observed discards but 80% of scavenging events. This study highlights factors influencing the frequency of dolphin scavenging events, guiding managers and scientists on additional studies and mitigation measures needed to address this issue.

Carcass use by mesoscavengers drives seasonal shifts in Australian alpine scavenging dynamics

Context Carrion is a high-energy and nutrient-rich resource that attracts a diverse group of vertebrate scavengers. However, despite the carrion pool being highly seasonal in its availability, there is little understanding of how scavengers utilise carcasses across all four seasons. Aim To assess how season influences carcass-detection times by vertebrate scavengers and their rates of scavenging. Methods We used remote cameras to monitor vertebrate scavenging at 15 eastern grey kangaroo (Macropus giganteus) carcasses in four consecutive seasons (summer, autumn, winter, and spring; total 58 carcasses) in the Australian Alps. Key results In total, 745 599 remote-camera images were captured, within which 34 vertebrate species were identified, nine of which were recorded to actively scavenge. Time to first detection of carcasses by vertebrate scavengers was 5.3 and 9.6 times longer during summer (average 144 h) than during spring (average 34 h) and winter (average 24 h) respectively. Rates of vertebrate scavenging were highest in winter and spring, with brushtail possums (Trichosurus vulpecula) accounting for 78% of all scavenging events during winter, and ravens (Corvus spp.) accounting for 73% during spring. High rates of carcass use by these mesoscavengers may reflect a scarcity of other food sources, the demands of their breeding season, or a relative absence of scavenging by larger dominant species such as dingoes (Canis dingo) and wedge-tailed eagles (Aquila audax). Conclusions These findings demonstrate the highly seasonal nature of vertebrate scavenging dynamics in an alpine ecosystem, and that mesoscavengers, not apex scavengers, can dominate the use of carcasses. Implications Accounting for the effects of season is integral to understanding the way animals utilise carcasses in alpine and other strongly seasonal environments; and for developing further our knowledge of ecosystem processes linked to decomposition.

Sperm whales (Physeteroidea) from the Pisco Formation, Peru, and their trophic role as fat sources for late Miocene sharks.

Shark-cetacean trophic interactions, preserved as bite marks in the fossil record, mostly correspond to isolated or fragmentary findings that bear limited information about major trophic patterns or roles. Here, we provide evidence of focalized foraging by sharks in the form of tooth bite marks over physeteroids fossil bones from the late Miocene of Peru. These findings indicate that sharks were targeting the forehead of coeval physeteroids to actively feed on their lipid-rich nasal complexes. Miocene physeteroids displayed a broad diversity, including giant predatorial forms, small benthic foragers and suction feeders. Like their extant relatives, these animals exhibited enlarged fatty forehead organs responsible for their sound production capabilities, thus evolving taxon-specific cranial architecture. Bite marks are found on the cranial bones where these structures were attached, indicating that sharks actively targeted this region; but also, in areas that would only be accessible following the consumption of the surrounding soft tissues. The shape of the bite marks and their distribution suggests a series of consecutive scavenging events by individuals of different shark species. Similar bite patterns can be recognized on other Miocene physeteroids fossils from across the globe, suggesting that sharks actively exploited physeteroid carcasses as fat sources.

Structure-function relationship of small peptides generated during the ripening of Spanish dry-cured ham: Peptidome, molecular stability and computational modelling

A systematic insight into the structure–function properties of small bioactive peptides is of great importance. Herein, peptidomics and computational methodology were adopted to investigate the stabilization patterns and building blocks of antioxidant peptides resulting from proteolysis during the ripening of Spanish dry-cured ham (9–24 months of processing). The results showed that native peptides underwent manufacture-induced steric/redox stress, while homogeneous/heterogeneous p-π/π-π interaction significantly improved the ABTS+ inhibition activity of hydrophobic peptides. However, for more hydrophilic peptides, the intrinsic π-interaction system (i.e., cation-π and π-π packing) substantially interfered with ABTS+/DPPH scavenging events when compared to the aromatic residues. Semi-quantitative peptidomics and molecular simulation/docking revealed that VFSSQGQSELILLQK and LCPSPDGLYL are two potential antioxidant peptides at the late ripening-drying. They had distinctive self-folding destinies following solvation owing to varying charged/hydrophobic properties of termini and hydrogen atom donor, allowing different flexibility of backbone and interactive surface towards free radicals ex situ followed by electron/proton transfer.

Biases in Bird-Window Collisions: A Focus on Scavengers and Detection Rates by Observers

Bird–window collisions (BWCs) represent a source of mortality for both resident and migratory birds that researchers aim to quantify. Factors that limit carcass detection, including removal of carcasses by scavengers and inherent error in observer detection, can complicate these efforts. We combined 2 studies to examine what proportion of carcasses were scavenged and removed and how successful observers were at detecting bird decoys of multiple types. In fall 2019 and spring 2020, we deployed 40 bird carcasses at Radford University campus buildings and monitored visitation events with game cameras for up to 4 nights/5 days. Scavengers visited 31 of the carcasses and scavenged (disturbed but not removed) 14/31. Scavengers included Felis catus (Domestic Cat, n = 6 events), Mephitis mephitis (Striped Skunk, n = 3), and Procyon lotor (Raccoon, n = 3). All mammalian scavenging events were nocturnal. Cats visited carcasses without disturbing them (n = 22 events), whereas Raccoons (3/3 events) and Striped Skunks (3/4) scavenged carcasses on discovery. Mammals scavenged or removed 3 carcasses in the first night after deployment (e.g., in the first 14 h), suggesting that scavenging can cause daily surveyors to miss ∼7.5% of carcasses. Across spring and fall 2020, we deployed 60 decoys of 4 unique types (varying in color or shape), partially obscuring them under shrubs and along landscaped herbaceous vegetation. We found that observers detected 48% of the decoys on their first attempts (min–max: 8.7–100%). Decoy type did not affect observer detection. By our estimates, 2 observers per day could have collectively missed 27% of carcasses. Although BWC projects typically complete surveys once or twice daily, we suggest twice-daily surveys when monitoring BWC during migratory seasons and once-daily surveys at other times to minimize carcass loss due to scavenging.

Govaniadine Ameliorates Oxidative Stress, Inflammation, and Kupffer Cell Activation in Carbon Tetrachloride-Induced Hepatotoxicity in Rats.

Liver diseases such as hepatic carcinoma are one of the main health problems worldwide. Herbal drugs are largely used to treat liver injury in the indigenous system of medicine and may provide lead compounds for hepatoprotective drug discovery. The present study is investigated to test the Corydalis govaniana Wall. extract, fraction, and isolate therapeutically active constituents to explore their hepatoprotective, anti-inflammatory, and antioxidant activities. For this purpose, the antioxidant activity of govaniadine, caseadine, caseamine, and protopine was performed by assessing the scavenging events of the stable 2,2-diphenyl-1-picrylhydrazyl. Hepatoprotection of govaniadine was assessed in terms of reduction in serum enzymes (alanine aminotransferase, aspartate transaminase, and alkaline phosphatase) caused by CCl4-induced liver injury in rats and by histopathological techniques. All the compounds showed significant antioxidant activity with a percentage inhibition of 92.2, 86.7, 85.3, and 79.7, respectively, compared to propyl gallate 90.3%. Treatment with govaniadine reduced the serum enzyme level down to normal levels in the CCl4-treated group while inhibiting the increase of malondialdehyde, and the induction of superoxide dismutase and the glutathione level was upregulated. Histopathology showed ∼47% damage to the liver cells in the CCl4-treated group; reduction in this damaged area was found to be better upon using govaniadine. Immunohistochemistry results showed that govaniadine as compared to silymarin has exceedingly decreased the inflammation by halting the CCl4-induced activation of hepatic macrophages. In carrageenan-induced paw edema assay, govaniadine significantly alleviated the edema after 1–5 h at a dose of 20 mg/kg (26.00 and 28.5%), 50 mg/kg (22.05 and 27.0%), and 100 mg/kg (20.02 and 25.30%), respectively. The results of our experiments suggest that govaniadine showed antioxidant and hepatoprotective activity in liver injury. The hepatoprotective function of govaniadine may be associated to the scavenging of the free radical and attenuation of oxidative stress as well as inflammatory responses in the liver. Hence, govaniadine may be a lead compound for the hepatoprotective drug discovery process and further research is needed to find out their molecular mechanism of protection.

Feeding traces on postcranial sauropod remains from Bajo de la Carpa Formation (Upper Cretaceous, Santonian), northern Neuquén Basin, Patagonia, Argentina

Bite marks in non-avian dinosaur fossil records can constitute the best evidence of predator-prey interactions even if they are uncommon, ambiguous, or of uncertain origin. In this contribution, we present new evidence of feeding traces on an isolated sauropod element from Bajo de la Carpa Formation outcrops (Upper Cretaceous, Santonian), northern Neuquén province, Patagonia, Argentina. The specimen is composed of a partial dorsal vertebral centrum (MAU-Pv–CO–651; deposited at the Museo Municipal Argentino Urquiza, Rincón de los Sauces, Neuquén, Argentina). We tentatively refer it to an indeterminate titanosaur sauropod due to the presence of an opisthocoelic articulation and an internal pneumatic camellate condition. Three kinds of marks are preserved on the lateroventral face of the centrum: large and deep parallel marks, small and shallow longitudinal marks, and deep oval holes that we tentatively consider as punctures. These fossil marks can be considered to be feeding traces produced by a large-bodied carnivore to deflesh the bone and/or to obtain bone nutrients, probably during a single scavenging event. The marks and the punctures on the vertebral centrum can be referred to a theropod dinosaur due to their pattern and distribution. Viavenator exxoni (Filippi et al., 2016) represents the most likely trace-maker candidate among the several theropod and crocodile taxa present in the Bajo de la Carpa Formation fossil record. The fossil feeding traces reported here improve our knowledge about the feeding behaviour of large scavengers in the north of the Neuquén Basin, at least during the Santonian.

Phase II spatial patterning of vulture scavenged human remains

This project expands on a pilot study by Spradley, Hamilton, and Giordano (2012) that investigated the patterns and effect of vulture scavenging of human remains, with special focus on the effect of microenvironments. Five donated bodies from the Willed Body Donation Program at Texas State University were placed in various locations at the university’s Forensic Anthropology Research Facility (FARF). The bodies were monitored by motion capture cameras and after each vulture scavenging event the dispersal and location of the bodies’ skeletal elements were mapped with a high accuracy GPS unit. The degree and direction of dispersal by vultures were then analyzed with GIS.Phase II revealed that vultures will begin scavenging at variable times, will continue to return to and move remains after a body has been skeletonized, and tend to move remains from higher elevations to lower elevations. The data also suggested that vultures may scavenge in larger groups (n > 20) in cooler temperatures, but in warm to hot temperatures they may scavenge more frequently in smaller groups (n ≈ 5). Future directions for vulture scavenging profiles are briefly discussed.

First observations of white sharks (Carcharodon carcharias) attacking a live humpback whale (Megaptera novaeangliae)

To date, white shark (Carcharodon carcharias) feeding events involving large whales have largely been described only in terms of observed scavenging events. Scavenging occurs in all ecosystems and is usually associated with stochastic feeding events. In marine ecosystems, whale carcasses commonly provide these community-wide food web events. Whale carcasses are the single largest source of carrion in marine ecosystems, to the extent that they are thought to constitute an important part of large white shark foraging ecology, shaping many aspects of the life history of the sharks, including adult migrations. However, to date, no part of this white shark feeding event has been described involving a live whale. To the best of our knowledge, here we provide the first published description of white sharks attacking and killing a live humpback whale (Megaptera novaeangliae). The attack displayed novel behaviours, including evidence of the ‘bite and spit’ tactic, rarely described in non-pinniped-related white shark feeding events before and all part of a tactical timeline of an attack that is precise, deliberate and effective.

Scavenging by Owls: A Global Review and New Observations from Europe and North America

Scavenging is an important ecological function that increases individual fitness and transfers energy between trophic levels. Scavenging by owls has been documented opportunistically through direct observations, camera trapping, and pellet analyses, but it is unknown how frequent or widespread the behavior is. We documented three new scavenging events from North America and Europe, and also performed a systematic literature review of the reports documenting scavenging by owls. The number of such reports was similar in each decade from the 1970s to the 2000s, but the decade of the 2010s had more reports than all previous decades combined. Owls scavenged primarily on mammals (81%), followed by birds (16%) and reptiles (3%); almost half (47%) of carrion scavenged were Artiodactyla (hoofed mammals) and most of the species scavenged were larger than the feeding owl. Most reports documenting scavenging by owls were from either Europe (n=14) or North America (n=11), with few reports from Asia (n=2), South America (n =2), or Australia (n=1), and none from Africa. The most frequent type of report was direct observations (n= 14), followed by camera trapping (n=9) and pellet analyses (n=6). Our review indicates that scavenging is a widespread behavior among owl species, but most observations were opportunistic, suggesting that additional incidents of scavenging by owls are likely unobserved. Further research is needed to establish the frequency of scavenging by owls and the effects that scavenging may have on owl populations and scavenging communities.

Global positioning system location clusters vs. scats: comparing dietary estimates to determine mesopredator diet in a conflict framework

AbstractStudying the feeding ecology of mesopredators living on or adjacent to farmland is important as livestock predation fuels conflict between farmers and predators and between diverse stakeholders on how to best manage this conflict. Most dietary studies on elusive and heavily persecuted predators rely on indirect methods such as scat analysis, because direct observations of predation events are rare. Consequently, the proportion of livestock and other prey that was actively hunted vs. scavenged remains largely unknown. We used data from global positioning system collars affixed to black‐backed jackal (Canis mesomelas) and caracal (Caracal caracal) to locate potential feeding sites on farmland and a protected area and to attempt to determine whether prey had been killed or scavenged. We compared dietary estimates from prey items found at global positioning system location clusters (GLCs) with those obtained from scat analysis and investigated whether GLC analysis is a suitable method to determine mesocarnivore diet. The success rate of finding a kill site when investigating GLCs was significantly higher for caracal than for jackal. Only 16.2% and 4.7% of jackal and caracal GLCs, respectively, were classified as scavenging events. Livestock was the most frequently detected prey in both scats and GLCs on farmland but GLCs provided a higher estimate of sheep biomass than scats. Caracal GLCs revealed prey ranging in size from small to large, whereas jackal GLCs were only for medium and large prey categories. Adult male caracals predated significantly more on livestock than females and younger individuals. Collared jackals residing in the protected area never formed GLCs containing livestock remains on neighbouring farms. Together, GLCs and scat analyses provide a more complete understanding of mesopredators feeding ecology on farmland. We recommend that both methods are applied, particularly in regions where livestock predation and lethal management of predators are driving conflict between stakeholders.

Whale carcass scavenging by sharks

Sharks are well known to scavenge whale carcasses, but observations are rare. Here we (1) describe new observations of whale carcass scavenging behaviour by white (Carcharodon carcharias) and tiger (Galeocerdo cuvier) sharks, and (2) review the scientific and grey literature on the topic. Our new observations are from the east coast of New South Wales, Australia and include a sperm whale (Physeter microcephalus) carcass in 2015, a humpback whale (Megaptera novaeangliae) carcass and fin whale (Balaenoptera physalus) carcass in 2018. Analysis of these observations revealed that feeding preferences differed among whale species for each species of shark. Feeding behaviour (including test biting, head shaking, palatoquadrate protrusion, ocular rotation and nictitating membrane use) were employed by both tiger and white sharks, with little inter or intraspecific aggression. Behaviour of sharks scavenging whale carcasses differs in the primary literature depending on whale carcass and species of shark present. Most of our results support past observations regarding feeding behaviours and little inter or intraspecific aggression. However, our results differed from past events. We observed increased palatoquadrate protrusion by white sharks and avoidance of flukes or pectoral fins feeding by tiger and white sharks. Review of the literature demonstrates that scavenging events are more commonly reported in grey literature than in scientific documents.

Not eating alone: Andean bear time patterns and potential social scavenging behaviors

Human-Andean bear ( Tremarctos ornatus ) conflicts are increasing due to the establishment of livestock or crops near to its natural habitats. Here we report scavenging time patterns of Andean bears and the potential social scavenging behaviors in Choachi and Guasca municipalities, Cundinamarca department, buffer zone of Chingaza National Natural Park, Colombia. Between 2013 -2015, we obtained 31 Andean bear scavenging events, allegedly related with human-bear conflict reports; most records occurred in Choachi municipality ( n = 29). Daily scavenging behaviors showed a heterogeneous pattern, where bears prefer to scavenge in morning hours (6:00 h-10:00 h) with small activity in the afternoon (15:00 h-17:00 h). Furthermore, we report on the first potential record of social activity of three adults scavenging on the same carcass at the same time with no aggressive/antagonistic behaviors between the individuals. Most aspects of Andean bear wild behaviors are still unknown; our observations represent interesting additions to the natural history of the species that could also be included in future programs for the mitigation and reduction of conflicts with human communities in the Andean region of Colombia.