Comparative analysis of the diet of feral and house cats and wildcat in Europe

Loss of Sunda clouded leopards and forest integrity drive potential impacts of mesopredator release on vulnerable avifauna

Amongst the unintended consequences of anthropogenic landscape conversion is declining apex predator abundance linked to loss of forest integrity, which can potentially re-order trophic networks. One such re-ordering, known as mesopredator release, occurs when medium-sized predators, also called mesopredators, rapidly increase in abundance following the decline in apex predator abundance, consequently reducing the abundance of mesopredator prey, notably including terrestrial avifauna. We examine the cascading impacts of declining Sunda clouded leopard abundance, itself consequent upon a reduction in forest integrity, on the mesopredator community of Sabah, Malaysia, to determine whether the phenomenon of mesopredator release is manifest and specifically whether it impacts the terrestrial avifauna community of pheasants and pittas. To explore this trophic interaction, we used a piecewise structural equation model to compare changes in the relative abundance of organisms. Our results suggest that loss of forest integrity may have broad impacts on the community and trigger mesopredator release, the two acting additively in their impact on already vulnerable species of terrestrial avifauna: a result not previously documented in tropical systems and rarely detected even on a global scale. The limiting effect that the Sunda clouded leopard has on the Sunda leopard cat could illuminate the mechanism whereby mesopredator release impacts this system. Both Bulwer's pheasant and pittas appear to be significantly impacted by the increase in Sunda leopard cats, while the great argus pheasant shows similar compelling, although not statistically significant, declines as Sunda leopard cats increase. The inverse relationship between Sunda clouded leopards and Sunda leopard cats suggests that if a mesopredator release exists it could have downstream consequences for some terrestrial avifauna. These results suggest the under-studied interface between mammalian carnivores and avifauna, or more broadly species interactions in general, could offer important conservation tool for holistic ecosystem conservation efforts.

Protein quality of a small mammal prey and its body organs for felids

This study evaluated the protein quality of small mammalian prey and its body organs by analyzing amino acid (AA) composition and digestibility of wild adult rats and their body organs (skin/fur, bone, muscle, intestine, liver, kidney, spleen, brain, heart, and lung) utilizing an in vitro digestion method. The average dry matter (DM) digestibility of whole rats was 89.9%. The digestibility of total AA (TAA), total indispensable AA (TIAA), and total dispensable AA (TDAA) in whole rats was 85.6, 87.0, and 87.6%, respectively. Differences in DM digestibility were observed among rat organs, ranging from 59.0% in bone to 99.8% in muscle (P < 0.001). Highly digestible organs generally exhibited AA digestibility exceeding 90%, except for cysteine (Cys) in the intestine and kidney (83.8% and 88.9%, respectively). The digestibility of AAs in skin/fur ranged from 19.7% for Cys to 81.0% for glycine (Gly). In bone, the digestibility spanned from 56.9% for Gly to 81.1% for tyrosine (Tyr). Additionally, examining the digestible indispensable AA score (DIAAS) gives us an idea of the protein quality of small mammalian prey and their body organs. Our results complement information on AA supply and digestion during prey ingestion by felids.

Consumption of Rodenticide Baits by Invertebrates as a Potential Route into the Diet of Insectivores

Non-target species are commonly exposed to anticoagulant rodenticides worldwide, which may pose a key threat to declining species. However, the main pathway of exposure is usually unknown, potentially hindering conservation efforts. This study aimed to examine whether baits mixed with the biomarker rhodamine B can be used to track invertebrate consumption of rodenticides in a field environment, using this to observe whether invertebrate prey are a potential vector for anticoagulant rodenticides in the diet of insectivores such as the European hedgehog (Erinaceus europaeus). Rhodamine B baits were found to create an observable response. Uptake was negligible in captured insects; however, 20.7% of slugs and 18.4% of snails captured showed uptake of bait. Maximum temperature, distance from bait, proximity to buildings, and the addition of copper tape to bait boxes all influenced the rate of bait uptake in molluscs. Based on these data, it seems likely that molluscs could be a source of rodenticide poisoning in insectivores. This research demonstrates which prey may pose exposure risks to insectivores and likely environmental factors, knowledge of which can guide effective mitigation measures. We suggest that further investigation into using mollusc repellents around bait boxes should be considered.

A dietary perspective of cat-human interactions in two medieval harbors in Iran and Oman revealed through stable isotope analysis

Cats are hypercarnivorous, opportunistic animals that have adjusted to anthropogenic environments since the Neolithic period. Through humans, either by direct feeding and/or scavenging on food scraps, the diet of cats has been enriched with animals that they cannot kill themselves (e.g., large mammals, fish). Here, we conducted carbon and nitrogen stable isotope ratio analysis to reconstruct the diet of medieval cats and investigate cat-human interactions in two medieval harbor sites (Qalhât, Oman and Siraf, Iran). The analysis included 28 cat individuals and 100 associated marine and terrestrial faunal samples pertaining to > 30 taxa. The isotopic results indicate a high marine protein-based diet for the cats from Qalhât and a mixed marine-terrestrial (C₄) diet for the cats from Siraf. Cats at these sites most likely scavenged on both human food scraps and refuse related to fishing activities, with differences in the two sites most likely associated with the availability of marine resources and/or the living conditions of the cats. By shedding light on the dietary habits of cats from two medieval harbors in the Arabian Gulf and Gulf of Oman, this study illustrates the potential of stable isotope analysis in reconstructing human-cat interactions in the past.

Response of a mesocarnivore community to a new food resource: recognition, exploitation, and interspecific competition

Mammalian carnivores with generalist feeding behaviour should trace and exploit new and predictable food resources quicker and more easily than more specialised species. On the other hand, if the new food resource is spatially and temporally predictable, interference or exploitation competition should arise among members of the carnivore guild, with the expectation that smaller species will not use the food resource or will change their foraging behaviour to avoid conflict with larger species. Here, we studied the response to a new food resource of a mammalian mesocarnivore community in south-western Iberian Peninsula. We installed artificial feeding points supplied with a novel food source and tracked them by camera trapping to investigate whether (1) the new artificial food resource was visited, recognised and exploited by the mesocarnivore guild species; (2) how frequently they used the food; and (3) in case of co-occurrence, if dominant species excluded or reduced the feeding options of subordinates. All target species except the badger recognised and exploited the novel food. More generalist species trended to visit feeding points more frequently and spent more time feeding than less generalist species, even though significant differences were not achieved in all cases. When co-occurring at the same feeding point, the arrival of larger species reduced either the visitation rates, feeding probability or time spent feeding of smaller species. Moreover, some smaller species showed a shift in their normal activity pattern at the feeding points when a larger competitor started to use the food source. Overall, we conclude that active avoidance combined with temporal segregation may help reduce agonistic interactions among competitors for shared resources.

Stable isotopes unveil one millennium of domestic cat paleoecology in Europe

The domestic cat is the world's most popular pet and one of the most detrimental predators in terrestrial ecosystems. Effective protection of wildlife biodiversity demands detailed tracking of cat trophic ecology, and stable isotopes serve as a powerful proxy in dietary studies. However, a variable diet can make an isotopic pattern unreadable in opportunistic predators. To evaluate the usefulness of the isotopic method in cat ecology, we measured C and N isotope ratios in hundreds of archaeological cat bones. We determined trends in cat trophic paleoecology in northern Europe by exploiting population-scale patterns in animals from diverse locations. Our dataset shows a high variability of isotopic signals related to the socio-economic and/or geomorphological context. This points toward regularities in isotopic patterns across past cat populations. We provide a generalized guide to interpret the isotopic ecology of cats, emphasizing that regional isotopic baselines have a major impact on the isotopic signal.

The wild ancestors of domestic animals as a neglected and threatened component of biodiversity

Domestic animals have immense economic, cultural, and practical value and have played pivotal roles in the development of human civilization. Many domesticates have, among their wild relatives, undomesticated forms representative of their ancestors. Resurgent interest in these ancestral forms has highlighted the unclear genetic status of many, and some are threatened with extinction by hybridization with domestic conspecifics. We considered the contemporary status of these ancestral forms relative to their scientific, practical, and ecological importance; the varied impacts of wild-domestic hybridization; and the challenges and potential resolutions involved in conservation efforts. Identifying and conserving ancestral forms, particularly with respect to disentangling patterns of gene flow from domesticates, is complex because of the lack of available genomic and phenotypic baselines. Comparative behavioral, ecological, and genetic studies of ancestral-type, feral, and domestic animals should be prioritized to establish the contemporary status of the former. Such baseline information will be fundamental in ensuring successful conservation efforts.

Use of molecular scatology to assess the diet of feral cats living in urban colonies

The overpopulation of domestic cats (Felis catus) presents a serious concern for wildlife conservationists, animal welfare advocates, public health officials, and community members alike. In cities, free-ranging, unowned cats often form high-density groups (commonly called ‘colonies’) around human provisioned food sources. While previous diet studies have primarily utilized morphology-based methods, molecular techniques offer a higher resolution alternative. In this study, we used next-generation sequencing techniques to examine the diet composition of feral cats living in five Trap-Neuter-Return colonies located in urban parks on Staten Island, a borough of New York City. We hypothesized that (1) cats living in urban colonies would still consume natural prey despite being regularly fed and (2) that the composition of taxa represented in the diet of each colony would vary, possibly due to differences in prey availability across sites. In total, 16 vertebrate prey taxa were identified in the diet, 13 at the genus level and 3 at the family level. Despite being regularly fed, 58.2% of cat scats contained DNA from natural prey. The diet composition of the cat colonies differed depending on the land cover composition surrounding the colony with the frequency of native prey positively correlated with the proportion of green space and that of non-native prey with developed land cover types. The use of molecular techniques combined with environmental DNA methods offers a promising, non-invasive approach to assessing the diet and consequently, impact of a highly abundant and non-native predator on the persistence of wildlife communities in cities.

Ancestors of domestic cats in Neolithic Central Europe: Isotopic evidence of a synanthropic diet

Cat remains from Poland dated to 4,200 to 2,300 y BCE are currently the earliest evidence for the migration of the Near Eastern cat (NE cat), the ancestor of domestic cats, into Central Europe. This early immigration preceded the known establishment of housecat populations in the region by around 3,000 y. One hypothesis assumed that NE cats followed the migration of early farmers as synanthropes. In this study, we analyze the stable isotopes in six samples of Late Neolithic NE cat bones and further 34 of the associated fauna, including the European wildcat. We approximate the diet and trophic ecology of Late Neolithic felids in a broad context of contemporary wild and domestic animals and humans. In addition, we compared the ecology of Late Neolithic NE cats with the earliest domestic cats known from the territory of Poland, dating to the Roman Period. Our results reveal that human agricultural activity during the Late Neolithic had already impacted the isotopic signature of rodents in the ecosystem. These synanthropic pests constituted a significant proportion of the NE cat's diet. Our interpretation is that Late Neolithic NE cats were opportunistic synanthropes, most probably free-living individuals (i.e., not directly relying on a human food supply). We explore niche partitioning between studied NE cats and the contemporary native European wildcats. We find only minor differences between the isotopic ecology of both these taxa. We conclude that, after the appearance of the NE cat, both felid taxa shared the ecological niches.

Spatial Segregation between Red Foxes (Vulpes vulpes), European Wildcats (Felis silvestris) and Domestic Cats (Felis catus) in Pastures in a Livestock Area of Northern Spain

Red foxes, European wildcats and domestic cats share cattle pastures for hunting in La Pernía Valley, northern Spain. To understand the mechanisms that allow the coexistence of these mesopredators in a habitat characterized by its anthropogenic modifications, we recorded sightings of these species in pastures in the summers of 2016, 2017, 2018 and 2019. We tested if the species preferred specific areas of pastures and if they exhibited any spatial segregation in the use of pastures. Red foxes did not show consistent preferences for any area of the pastures. European wildcats preferred pasture areas closer to streams and forest edges, whereas domestic cats preferred areas closer to buildings and paved roads whilst avoiding forest edges. All species pairs showed strong spatial segregation with less than 7% overlap. We hypothesize that spatial segregation is the mechanism used by European wildcats and domestic cats to avoid dangerous interactions with other predators and which characterizes their preference of specific areas on pastures, using areas near places that may protect them from other predators. Ultimately, the influence of fox presence (and probably that of other larger potential predators) on the use of pastures by European wildcats and domestic cats is decreasing the number of interactions between them and may help to prevent hybridization in this area.

Analysis of cat diet across an urbanisation gradient

The domestic cat is a widespread and abundant predator that negatively impacts a wide range of species. However, the predation activity and prey type of free-ranging cats may vary between areas with different levels urbanisation. Previous analyses of cat diet have used differing techniques to measure predation that often differ with one another. Given the variability in these methods we hypothesised that cats in rural areas will have a more diverse diet than in urban areas and their predation rate may be higher than those in the urban sites. Moreover, we hypothesized that the diet of urban cats should be highly influenced by anthropogenic food. We selected sites across a rural-to-urban gradient and used three methods of analysis to determine prey in the diet (cat stomachs, cat scats, and prey brought home). We collected 81 stomachs, 409 scats, and 337 prey items of free-roaming cats from six study sites located in southern and eastern Poland. We found seasonal and habitat related differences in prey composition. The proportion of scats and stomachs containing vertebrate varied from 17% in urban areas to 79% in one of the rural areas. Small rodents were the dominant prey category, followed by birds and soricomorphs. Anthropogenic food was found to be an important part of urban cats’ diet, but its significance decreased with a decrease in urbanisation level. Both predation rate and prey diversity were highest in rural areas. While diet analysis provided a better estimation of cat predation rate, the detailed prey examination provided better insight into less common taxa killed by the cats, such as reptiles and small mustelids. Our results contribute to the discussion about the risks associated with the activity of free ranging cats especially in areas with high conservation values.

Evidence for Individual Differences in Behaviour and for Behavioural Syndromes in Adult Shelter Cats

Simple Summary

An important activity of modern animal shelters is the development of successful adoption programmes. In this regard, there is a need for reliable tests of individual differences in behaviour to help match the “personality” of potential adoptees with the lifestyle and needs of prospective owners; a companion animal for an elderly person remaining at home requires a different match than a pet for someone who will be away most of the day; a pet kept exclusively indoors in a small apartment requires a different match than an indoor/outdoor pet. In the present study, we repeatedly tested 31 mixed-breed adult cats of both sexes and a wide range of ages in five behavioural tests at a shelter in Mexico City, Mexico. The tests were designed to be easily implemented by shelter staff, and were short and low cost and intended to simulate common situations in a pet cat’s everyday life. We found consistent (stable) individual differences in the cats’ behaviour on all five tests, as well as correlations between their behaviour across tests. This suggests that such tests may contribute to reliably characterizing the “personality” of individual cats and so help increase the rate of successful adoptions.

Abstract

Consistent inter-individual differences in behaviour have been previously reported in adult shelter cats. In this study, we aimed to assess whether repeatable individual differences in behaviours exhibited by shelter cats in different situations were interrelated, forming behavioural syndromes. We tested 31 adult cats in five different behavioural tests, repeated three times each: a struggle test where an experimenter restrained the cat, a separation/confinement test where the cat spent 2 min in a pet carrier, a mouse test where the cat was presented with a live mouse in a jar, and two tests where the cat reacted to an unfamiliar human who remained either passive or actively approached the cat. Individual differences in behaviour were consistent (repeatable) across repeated trials for each of the tests. We also found associations between some of the behaviours shown in the different tests, several of which appeared to be due to differences in human-oriented behaviours. This study is the first to assess the presence of behavioural syndromes using repeated behavioural tests in different situations common in the daily life of a cat, and which may prove useful in improving the match between prospective owner and cat in shelter adoption programmes.

Revisiting more or less: influence of numerosity and size on potential prey choice in the domestic cat

Quantity discrimination is of adaptive relevance in a wide range of contexts and across a wide range of species. Trained domestic cats can discriminate between different numbers of dots, and we have shown that they also spontaneously choose between different numbers and sizes of food balls. In the present study we performed two experiments with 24 adult cats to investigate spontaneous quantity discrimination in the more naturalistic context of potential predation. In Experiment 1 we presented each cat with the simultaneous choice between a different number of live prey (1 white mouse vs. 3 white mice), and in Experiment 2 with the simultaneous choice between live prey of different size (1 white mouse vs. 1 white rat). We repeated each experiment six times across 6 weeks, testing half the cats first in Experiment 1 and then in Experiment 2, and the other half in the reverse order. In Experiment 1 the cats more often chose the larger number of small prey (3 mice), and in Experiment 2, more often the small size prey (a mouse). They also showed repeatable individual differences in the choices which they made and in the performance of associated predation-like behaviours. We conclude that domestic cats spontaneously discriminate between the number and size of potential prey in a way that can be interpreted as adaptive for a lone-hunting, obligate carnivore, and show complex levels of risk-reward analysis.