Facultative predation and scavenging by mammalian carnivores: seasonal,regional and intra‐guild comparisons

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狒狒圈舍废弃栖杠的嗅觉丰容对圈养食肉动物行为的影响

单调的饲养环境是导致圈养食肉动物表现刻板行为的主要原因之一。为减少圈养动物刻板行为的发生,探索便于操作、经济且有效的丰容方式是动物饲养管理者面临的一个挑战。本研究以狒狒圈舍废弃栖杠作为嗅觉丰容材料,对北京动物园小型(9种)、中型(4种)和大型(7种)食肉动物进行嗅觉丰容实验。在非投喂时段,采用扫描动物取样和瞬时记录法,分别对28只动物在丰容前后的5种行为进行观察和比较分析。结果显示,小型和中型食肉动物在丰容后对旧设施的使用频次显著下降(小型：P=0.026;中型：P=0.038),而大型食肉动物无显著变化(P> 0.05)。仅小型食肉动物的刻板性走动、休息和观望行为频次显著下降(走动：P=0.023;休息：P=0.023;观望：P=0.017),其他类群的各类行为均无显著变化(P> 0.05)。同时,丰容后小型食肉动物的行为多样性指数显著降低(P=0.008),主要表现为动物花费较多的时间探究新的丰容设施;中型和大型食肉动物的行为多样性指数变化不显著。结果表明,使用带有狒狒身体气味的栖杠进行嗅觉丰容,仅对小型食肉动物有效,对中型和大型食肉动物无效。研究认为,以其他动物圈舍的...     

The evolution of cursorial carnivores in the Tertiary: implications of elbow-joint morphology

The evolution of cursorial adaptations in Tertiary (65-1.65 Myr ago) carnivores has been a contentious issue. Most such studies have focused on the relationship between hind limb proportions and running speed. Here, we show morphometrically that in extant carnivores, the elbow joint has evolved in two distinct directions with mutually exclusive implications for locomotor ability and prey procurement. Some carnivores retain supinatory ability, allowing them to manipulate prey and other items with the forepaws. Such carnivores can become very large. Other carnivores lose the ability to supinate and become cursors. This allows for only moderate size increase. Modern carnivores above ca. 20 kg body mass are committed to one or other of these strategies. This threshold coincides with a postulated threshold in carnivore physiology. The biaxial pattern mostly follows phylogenetic lines, but a strong selective regime can override this signal, as shown by the extant cheetah. Oligocene (33.7-23.8 Myr ago) and early-middle Miocene (23.8-11.2 Myr ago) carnivores follow the same pattern, though in the Miocene the pattern is shifted towards larger body mass, which may be owing to the extraordinary richness of browsing ungulates at this time.     

Trophic Cascades in Terrestrial Systems: A Review of the Effects of Carnivore Removals on Plants

We present a quantitative synthesis of trophic cascades in terrestrial systems using data from 41 studies, reporting 60 independent tests. The studies covered a wide range of taxa in various terrestrial systems with varying degrees of species diversity. We quantified the average magnitude of direct effects of carnivores on herbivore prey and indirect effects of carnivores on plants. We examined how the effect magnitudes varied with type of carnivores in the study system, food web diversity, and experimental protocol. A metaanalysis of the data revealed that trophic cascades were common among the studies. Exceptions to this general trend did arise. In some cases, trophic cascades were expected not to occur, and they did not. In other cases, the direct effects of carnivores on herbivores were stronger than the indirect effects of carnivores on plants, indicating that top-down effects attenuated. Top-down effects usually attenuated whenever plants contained antiherbivore defenses or when herbivore species diversity was high. Conclusions about the strength of top-down effects of carnivores varied with the type of carnivore and with the plant-response variable measured. Vertebrate carnivores generally had stronger effects than invertebrate carnivores. Carnivores, in general, had stronger effects when the response was measured as plant damage rather than as plant biomass or plant reproductive output. We caution, therefore, that conclusions about the strength of top-down effects could be an artifact of the plant-response variable measured. We also found that mesocosm experiments generally had weaker effect magnitudes than open-plot field experiments or observational experiments. Trophic cascades in terrestrial systems, although not a universal phenomenon, are a consistent response throughout the published studies reviewed here. Our analysis thus suggests that they occur more frequently in terrestrial systems than currently believed. Moreover, the mechanisms and strengths of top-down effects of carnivores are equivalent to those found in other types of systems (e.g., aquatic environments).     

Carnivore taphonomy in South America: a review of actualistic studies and their implications in the southern Neotropics

Abstract

Actualistic studies on mammalian carnivore taphonomy in southern South America are reviewed here, including pumas, small cats, foxes, and other, smaller carnivores. Patterns for different carnivore taxa and their variation are elicited. Also temporal and spatial variability is analysed, and comparisons are made to other carnivores and regions. While generally these Neotropical carnivores produce low damage intensity, stronger modifications and their implications are described as well. These patterns and their variation are put in context by taking into account the particular physical and biotic conditions in the southern Neotropics.     

Evolution of skull shape in carnivores 2. Additional modern carnivores

Fifteen functionally significant aspects of skull morphology were measured on skulls of 36 additional species of carnivores to complete a survey of skull shape in modern fissiped (land) carnivores that includes most of the living genera. The measurements were transformed to dimensionless variables based on the residuals from allometric equations, and were analysed singly and in a 10 variable principal components analysis. An initial study of 62 species of viverrids, canids, mustelids and felids had shown those families to be distinguished from each other by the functionally significant measurements. However, among the additional 36 species, some procyonids, ursids and mustelids display a range of diversity of skull morphology that overlaps that of the other families and diminishes the potential value of the measurements as taxonomic characters. Intraspecific variation is presented for 12 species, and is low enough to allow use of some features as species level diagnostic characters. The lack of correlation between diet and functionally significant aspects of skull morphology among omnivorous carnivores, and the absence of certain skull shapes among carnivores are discussed.     

Function of the digastric muscle in carnivores

The general form and adaptation of the digastric muscle in carnivores are reviewed and discussed. The digastric muscle differs from the general plan in certain aquatic carnivores and felids. In the pertinent aquatic species the muscle is enlarged. The observations suggest that the enlargement is an adaptation for rapidly opening the jaws against the resistance of water. In felids, the insertion of the muscle is much farther forward than in most other carnivores. The observations suggest that the development of short jaws in felids necessitated a compensatory anterior relocation of the digastric insertion in order to preserve the ability to achieve a large gape.     

Conservation of biodiversity in Scandinavian boreal forests: large carnivores as flagships, umbrellas, indicators, or keystones?

Large carnivores are often used as focal species (indicators, umbrellas, flagships or keystones) in conservation strategies either aimed at conserving carnivores, the rest of the biodiversity that occupies their habitats, or both. We evaluate their suitability for these roles in the context of boreal forest biodiversity conservation in the muti-use landscapes of Scandinavia. The enormous conflicts, especially with livestock, that carnivores cause in these areas makes them very controversial flagships to the extent that it may affect rural people's attitudes to conservation in general. Because of the broad habitat tolerance of large carnivores and their prey, and the difficulties in surveying carnivore numbers, they are very insensitive and impractical indicators of forest biodiversity. This ability of large carnivores to thrive in industrial forests means that the many species that are sensitive to modern forestry will not fall under the umbrella of areas managed for large carnivores. If large carnivores have a keystone function with respect to affecting the density of their ungulate prey it is likely to lead to even further conflicts with hunters who gain economic benefit from harvesting wild ungulates. In other words, none of the classic `ecological' arguments are likely to help justify large carnivore conservation, and large carnivore conservation is unlikely to help conserve the rest of the boreal forest's biodiversity. Based on these arguments we recommend that (1) justification for large carnivore conservation focus on the real philosophical and value orientated reasons rather than ecological justifications, (2) that this conservation should be brought about in practice by dedicated management programs that specifically address the conflicts caused by large carnivores, and (3) that boreal forest biodiversity is best conserved by specific actions designed to establish reserves or change forestry practices.     

Chromosomal rearrangements and karyotype evolution in carnivores revealed by chromosome painting

Chromosomal evolution in carnivores has been revisited extensively using cross-species chromosome painting. Painting probes derived from flow-sorted chromosomes of the domestic dog, which has one of the most rearranged karyotypes in mammals and the highest dipoid number (2n=78) in carnivores, are a powerful tool in detecting both evolutionary intra- and inter-chromosomal rearrangements. However, only a few comparative maps have been established between dog and other non-Canidae species. Here, we extended cross-species painting with dog probes to seven more species representing six carnivore families: Eurasian lynx (Lynx lynx), the stone marten (Martes foina), the small Indian civet (Viverricula indica), the Asian palm civet (Paradoxurus hermaphrodites), Javan mongoose (Hepestes javanicas), the raccoon (Procyon lotor) and the giant panda (Ailuropoda melanoleuca). The numbers and positions of intra-chromosomal rearrangements were found to differ among these carnivore species. A comparative map between human and stone marten, and a map among the Yangtze finless porpoise (Neophocaena phocaenoides asiaeorientalis), stone marten and human were also established to facilitate outgroup comparison and to integrate comparative maps between stone marten and other carnivores with such maps between human and other species. These comparative maps give further insight into genome evolution and karyotype phylogenetic relationships among carnivores, and will facilitate the transfer of gene mapping data from human, domestic dog and cat to other species.     

Analysing stakeholders’ perceptions of wolf,lynx and fox in a Dutch riverine area

In the last decades, populations of large carnivores have been making a spectacular return, especially in the USA and Western Europe. These population recoveries result partially from protective legislation and reintroduction programs, but possibly also from land use changes and from large carnivores adapting to human environments. Although public support for large carnivore protection seems to be growing, some stakeholders still have a negative perception of large carnivores because of their alleged negative impacts on livestock and humans. Perceptions of large carnivores are partly determined by underlying visions of nature which differ between stakeholder groups. We therefore examined the relationship between different stakeholder groups’ perceptions of nature and the presence of the fox (Vulpes vulpes), and the possible establishment of the wolf (Canis lupus) and lynx (Lynx lynx) in a Dutch riverine landscape. Stakeholder groups comprised the general public, farmers, scientists and nature conservationists. Although perceptions of large carnivores differed significantly across the stakeholder groups, public support for large carnivores was generally higher than expected. Farmers show the most negative perception, especially regarding the wolf and lynx. This is related to their vision of nature, which is more strongly aligned with mastery over nature compared to other stakeholder groups. Scientists, prominent adherers of stewardship of nature, appear to have the most positive perception of large carnivores. Despite these differences in visions of nature, respondents generally adhere to the stewardship of nature relationship. This could be a good starting point to find common ground when disputes arise over large carnivores.     

Diet choice of large carnivores in northern Cameroon

The diet of African wild dogs, lions and spotted hyenas was studied in the woodland savannah of Faro National Park and surrounding hunting zones in northern Cameroon during the dry season. Faecal analysis revealed that the diet of the three large carnivores overlaps considerably. Frequencies of prey remains of large and medium‐sized antelopes were highest, with Buffon's kob being by far the most common prey species. Carnivores seem to consume the most abundant prey species. No prey item of domestic livestock was found in the faeces. Faecal analysis has proved to be a useful method to reveal diet choice for large carnivores in northern Cameroon. Detailed information on the distribution and density of large carnivores and their prey is needed to give a better picture of the status of carnivores in northern Cameroon and to help resolve conflicts with livestock. Further investigations into the seasonal variation of predation and other factors structuring the large carnivore community in northern Cameroon are recommended.     

Diet choice of large carnivores in northern Cameroon

The diet of African wild dogs, lions and spotted hyenas was studied in the woodland savannah of Faro National Park and surrounding hunting zones in northern Cameroon during the dry season. Faecal analysis revealed that the diet of the three large carnivores overlaps considerably. Frequencies of prey remains of large and medium‐sized antelopes were highest, with Buffon's kob being by far the most common prey species. Carnivores seem to consume most abundant prey species. No prey item of domestic livestock was found in the faeces. Faecal analysis has proved to be a useful method to reveal diet choice for large carnivores in northern Cameroon. Detailed information on the distribution and density of large carnivores and their prey is needed to give a better picture of the status of carnivores in northern Cameroon and to help resolve conflicts with livestock. Further investigations into the seasonal variation of predation and other factors structuring the large carnivore community in northern Cameroon are recommended.     

Presence of rabies neutralizing antibodies in wild carnivores following an outbreak of bovine rabies.

In an outbreak of bovine rabies in Argentina, a study was made of vampire bats (Desmodus rotundus) and wild carnivores. Rabies antibody rates of high prevalence were found in the bats, foxes (Dusicyon gymnocercus) and skunks (Conepatus chinga). The outbreak was part of an extensive continuing epizootic of vampire transmitted bovine rabies which may have also involved other vectors in the area of this study. Consumption of dead and dying bats by the carnivores is the suggested means of passage of rabies virus from vampire bats to foxes and skunks. Given optimum conditions it is conceivable that some outbreaks in carnivores may begin in this way.     

Surplus killing by carnivores

In several field observations, foxes, Spotted hyaenas and other carnivores killed many more prey individuals than they could eat. Functional and causal aspects of this phenomenon are discussed and the conclusion is reached that these surplus kills are the consequence of behavioural compromises in both predator and prey to meet opposing environmental requirements.  

Summary:

(1) Observations are reported in which carnivores killed considerably more prey animals than they could possibly eat, and causal and functional aspects of this behaviour are discussed. The species concerned were especially foxes and Spotted hyaenas, and references are quoted about surplus killing by other Canidae, Felidae and Ursidae.
(2) It is argued that satiation in carnivores does not inhibit further catching and killing , but it probably does inhibit searching and hunting. Thus carnivores are able to procure an "easy prey" but normally satiation limits numbers killed.
(3) Many, if not all, carnivores possess behaviour patterns which allow utilization of a kill at a later time, or allow other members of the same social unit or offspring to use the food.
(4) Several prey species showed a lack of anti-predator reaction under particular climatological circumstances; it is argued that this lack of response usually has survival value. Sometimes anti-predator behaviour is accidentally made ineffective.
(5) Surplus kills are made possible by (2) and (4) above, and only very rare circumstances give a predator access to so many prey that (3) is ineffective. It is suggested that surplus kills are the consequence of behavioural compromises in both predator and prey to meet opposing environmental requirements.     

Assessing resource and predator effects on habitat use of tropical small carnivores

Habitat use of animals is influenced by a combination of factors including food abundance and interactions with other species. Animals typically must forage while simultaneously avoiding predation from multiple potential predators, but habitat use in tropical forest ecosystems that assesses effects of both predation risk and resources has rarely been conducted. We used camera traps and occupancy analyses to document small mammalian carnivore occurrence in relation to food abundance and interactions with large predators. We hypothesized that habitat use of six small mammalian carnivores (≤15 kg) would be influenced by (1) abundance of resources (fruit, rodents, and streams) and/or (2) large predators. Predictions regarding food and habitat resources were only supported for one species (crab-eating mongoose, Urva urva), which was positively associated with rodents and streams. Three small carnivores (masked palm civet Paguma larvata, common palm civet Paradoxurus hermaphroditus, yellow-throated marten Martes flavigula) were affected negatively by leopard and mesopredators as predicted. Counter to our predictions, two species (masked palm civet and yellow-throated marten) showed spatial avoidance of tiger suggesting that an apex predator might also pose predation risk to small carnivores. The focal small carnivores and large predators of this study appeared to have moderately to highly overlapping temporal activity indicating no temporal avoidance. In conclusion, food resources appeared to have minimal effects for six small carnivores in this ecosystem probably due to continuous resource availability. Predation risk appeared to affect some species in terms of spatial occupancy but not in temporal activity, indicating perhaps complex, but not entirely negative interactions between larger carnivores and this guild of small carnivores. The mechanisms which facilitate co-occurrence between small carnivores and large predators may, however, operate at finer spatiotemporal scales than we investigated here.     

Seasonal occupancy of sympatric larger carnivores in the southern San Andres Mountains,south-central New Mexico,USA

We investigated factors facilitating coexistence of pumas (Puma concolor), coyotes (Canis latrans), and bobcats (Lynx rufus) in the arid San Andres Mountains of south-central New Mexico, during the season (winter and spring, prior to the annual monsoon) of greatest resource stress. We established a camera-trapping grid in the San Andres, 2007–2011, and modeled occupancy of the three carnivores as a function of habitat, prey, and presence of the other carnivore species. Species interaction factors were >1.3 for each pair of carnivores, and the presence of the other carnivore species never significantly influenced occupancy of any other carnivore. Similarly, occupancy of the San Andres landscape was positively correlated among all carnivores. Occupancy of pumas was most influenced by proximity of water; coyote occupancy was influenced by terrain ruggedness and presence of medium (primarily lagomorph) prey, and bobcat occupancy was influence primarily small prey and proximity to water. The three carnivores also did not show temporal partitioning in use of habitats. Rather than segregation driven by competition, predation, or despotism, our results appeared to reflect preferences for differing habitat characteristics between ambush and cursorial predators and preferred habitats for travel.     

Étude taphonomique, paléoécologique et archéozoologique des faunes de grands mammifères de la seconde moitié du Pléistocène inférieur de la grotte du Vallonnet (Roquebrune-Cap-Martin, Alpes-Maritimes, France)

Vallonnet cave (Alpes-Maritimes, France) provided archaic lithic tools together with a big amount of large mammals of the end of lower pleistocene. At the crossing of diverse ecological niches in time and space, three main levels and within them several smaller units were distinguished. The poorly mineralized bones witnessed a huge diagenetic fragmentation. The presence of the animals in the cave seems to be linked to the reasons of their death. The exhaustive and systematic observation of the bones, like the bears probably used to die inside the cave. Some other carnivores especially hyenas, used the cave as a nursery. Man also occupied the cave and had an activity mainly on large cervid bones and on some other species as well. The very progressive deposit gave a way for carnivores and porcupine to gnaw the bones on the ground before their burial. The succession of actions (man, carnivores and porcupine) on the same bones is characteristic on Vallonnet large mammals bones.     

Molecular Inferences Suggest Multiple Host Shifts of Rabies Viruses from Bats to Mesocarnivores in Arizona during 2001–2009

In nature, rabies virus (RABV; genus Lyssavirus, family Rhabdoviridae) represents an assemblage of phylogenetic lineages, associated with specific mammalian host species. Although it is generally accepted that RABV evolved originally in bats and further shifted to carnivores, mechanisms of such host shifts are poorly understood, and examples are rarely present in surveillance data. Outbreaks in carnivores caused by a RABV variant, associated with big brown bats, occurred repeatedly during 2001–2009 in the Flagstaff area of Arizona. After each outbreak, extensive control campaigns were undertaken, with no reports of further rabies cases in carnivores for the next several years. However, questions remained whether all outbreaks were caused by a single introduction and further perpetuation of bat RABV in carnivore populations, or each outbreak was caused by an independent introduction of a bat virus. Another question of concern was related to adaptive changes in the RABV genome associated with host shifts. To address these questions, we sequenced and analyzed 66 complete and 20 nearly complete RABV genomes, including those from the Flagstaff area and other similar outbreaks in carnivores, caused by bat RABVs, and representatives of the major RABV lineages circulating in North America and worldwide. Phylogenetic analysis demonstrated that each Flagstaff outbreak was caused by an independent introduction of bat RABV into populations of carnivores. Positive selection analysis confirmed the absence of post-shift changes in RABV genes. In contrast, convergent evolution analysis demonstrated several amino acids in the N, P, G and L proteins, which might be significant for pre-adaptation of bat viruses to cause effective infection in carnivores. The substitution S/T₂₄₂ in the viral glycoprotein is of particular merit, as a similar substitution was suggested for pathogenicity of Nishigahara RABV strain. Roles of the amino acid changes, detected in our study, require additional investigations, using reverse genetics and other approaches.     

When carnivores are “full and lazy”

Are animals usually hungry and busily looking for food, or do they often meet their energetic and other needs in the 24 h of a day? Focusing on carnivores, I provide evidence for the latter scenario. I develop a model that predicts the minimum food abundance at which a carnivore reaches satiation and is released from time constraints. Literature data from five invertebrate and vertebrate species suggest that food abundances experienced in the field often exceed this threshold. A comparison of energetic demands to kill rates also suggests that carnivores often reach satiation: for the 16 bird and mammal species analyzed, this frequency is 88% (average across species). Because pressure of time would likely lead to trade-offs in time allocation and thus to a nonsatiating food consumption, these results suggest that carnivores are often released from time constraints.     

Differences in diet and trophic interactions of Patagonian carnivores between areas with mostly native or exotic prey

The prey base for Patagonian carnivores has been altered greatly over the past 150 years due to widespread overgrazing by livestock, invasions by exotic wildlife, and hunting. On ranches in northern Patagonia carnivores consume mostly exotic species, and native herbivores are ecologically extinct in their role as prey. In this study we compare diets of the culpeo (Lycalopex culpaeus), chilla (L. griseus), puma (Puma concolor), Geoffroy's cat (Leopardus geoffroyi), colocolo (L. colocolo), and hog-nosed skunks (Conepatus chinga and C. humboldtii) in a reserve with a mostly native prey base to their diets on the ranches, and evaluate how differences in prey bases affect trophic interactions among carnivores. Carnivores in the reserve consumed mostly native prey. Dietary overlap among carnivores was not significant on the reserve, but was highly significant on the ranches. This homogenization of diets where densities of native species are reduced could lead to stronger negative interactions among carnivores, altering the composition of the carnivore assemblage to the detriment of the more specialized species. Study of carnivore diets may be a relatively quick way to evaluate the conservation status and ecological functionality of prey assemblages in Patagonia and other areas where these have been altered.