Unowned Cats Research Articles

Coexistence between Humans and 'Misunderstood' Domestic Cats in the Anthropocene: Exploring Behavioural Plasticity as a Gatekeeper of Evolution.

Simple SummaryThe free-ranging unowned domestic cat (unowned—not under human control with respect to movement and sexual behaviour), living in the Anthropocene, can live a strictly solitary life or in socially structured groups, depending on environmental conditions. This paper explores the evidence for evolution of new traits (behavioural, morphological, physiological, immunological) in domestic cats, to adapt to the variety of ecosystems they now successfully inhabit. While the domestic cat ancestor lived a strictly solitary life, unowned free-ranging cats today may live in multi-male/multi-female colonies in urban city centres, where they are dependent on food provided by people. Urban free-ranging cats are now more social, which has been reflected in different breeding patterns, lower infanticide, more frequent affiliative interactions in general, and different spatial groupings. This means there is a potential for domestic cat behaviour to be ‘misunderstood’. Recognising that negative impacts of free-ranging domestic cats in urban fringe areas must be mitigated, we discuss how understanding behavioural plasticity and other recently evolved traits of domestic cats may lead to management strategies that maximise health and welfare of cats, wildlife, and humans.Welfare and management decisions for unowned free-ranging cats in urban environments should no longer be based on knowledge about behavioural ecology of solitary cats living and breeding in more natural ‘wild’ environments. We provide evidence that urban free-ranging domestic cats in the Anthropocene have responded to rapidly changing environments, such as abundance of food and higher population densities of conspecifics by adapting their behaviour (behavioural plasticity—the ability of a genotype (individual) to express different behaviours according to its environment) and social organisation to living in complex social groups, especially those living in colonies. Urban free-ranging cats are now more social, as demonstrated by different breeding patterns, lower infanticide, more frequent affiliative interactions in general, and different spatial groupings. We argue that this knowledge should be disseminated widely, and inform future research and strategies used to manage free-ranging cats across environments. Understanding behavioural plasticity and other recently evolved traits of domestic cats may lead to management strategies that maximise health and welfare of cats, wildlife, and humans—otherwise domestic cat behaviour may be ‘misunderstood’. Importantly, interdisciplinary research using expertise from biological and social sciences, and engaging human communities, should evaluate these management strategies to ensure they maintain optimal welfare of free-ranging domestic cats while preserving biodiversity and protecting wildcats.

Review and synthesis of the global literature on domestic cat impacts on wildlife

A vast global literature documents that free-roaming domestic cats (Felis catus) have substantial negative effects on wildlife, including through predation, fear, disease and competition-related impacts that have contributed to numerous wildlife extinctions and population declines worldwide. However, no study has synthesized this literature on cat impacts on wildlife to evaluate its overarching biases and major gaps. To direct future research and conservation related to cat impacts on wildlife, we conducted a global literature review that entailed evaluation and synthesis of patterns and gaps in the literature related to the geographic context, methods and types of impacts studied. Our systematic literature search compiled 2245 publications. We extracted information from 332 of these meeting inclusion criteria designed to ensure the relevance of studies analysed. This synthesis of research on cat impacts on wildlife highlights a focus on oceanic islands, Australia, Europe, and North America, and on rural areas, predation, impacts of unowned cats, and impacts at population and species levels. Key research advances needed to better understand and manage cat impacts include more studies in underrepresented, highly biodiverse regions (Africa, Asia, and South America), on cat impacts other than predation, and on methods designed to reduce impacts on wildlife. The identified areas of needed research into cat impacts on wildlife will be critical to further clarifying the role of cats in global wildlife declines and to implementing science-driven policy and management that benefit conservation efforts.

Estimating the Population of Unowned Free-Ranging Domestic Cats in Denmark Using a Combination of Questionnaires and GPS Tracking.

Simple SummaryUnowned free-ranging domestic cats divide opinion. Some people object to them. They dislike the noise they cause and disapprove when they find their faeces in gardens and public places. Others are concerned about the cats’ welfare. It is widely believed that the number of unowned unsocialised cats (alleged to be 500,000) and additional unowned socialised cats in Denmark is huge. To assess whether this belief is correct, this study estimated the size of the population of unowned free-ranging domestic cats and their distribution in Denmark using a combination of questionnaires and GPS tracking. It was estimated that approximately 90,000 unowned cats are in the country, and that one-third are socialised and two-thirds unsocialised. It seems therefore that the number of free-ranging cats in Denmark that are unowned and unsocialised is only a fraction of that claimed, and that panic is unwarranted. The highest population density of unowned cats was found in rural areas.The present study aimed (1) to estimate the size of the population of unowned free-ranging domestic cats in Denmark using a questionnaire survey combined with a GPS-tracking survey, and (2) to estimate the distribution of the population across different habitats. The questionnaires were circulated in 94 randomly selected parishes ranging across seven kinds of habitat. Using responses from five of the habitats, we estimated the population of unowned free-ranging cats nationally. In the other two habitats, questionnaire data were collected in a simpler way. The territory of 59 owned cats was estimated with GPS tracking to assess home ranges. Home range area was calculated using 95% Brownian bridge kernel density estimation (0.033–0.077 ± 0.011–0.023 km2, median ± SE). We estimated a population of unowned free-ranging cats in Denmark of 89,000 ± 11,000 (SE), with a mean density of 2 ± 0.3 (SE) cats per km2, living primarily in rural habitats. Approximately one-third of the cats were estimated to be socialised and two-thirds unsocialised. Our method may be suitable for use in other temperate areas facing problems with unowned free-ranging cats.

Sanitation is the greatest concern in outdoor cat management but ecological message frames promote biodiversity conservation in Japan

SummaryMessage framing contributes to an increase in public support for invasive species management. However, little is known about people’s preferences for the multiple objectives of management within different contexts relating to the challenges and benefits of invasive species management. We examine Japanese citizens’ preferences for the goals of free-roaming unowned cat (Felis catus) management in three contextual frames by applying experimentally controlled information and the best–worst scaling technique. Our results indicate that the ecological frame highlighting the ecological impacts of free-roaming unowned cats on native ecosystems significantly increases Japanese citizens’ concern about cat predation, although the frame did not change the preference ranking of goals. There are differences in the effects of message framing depending on cat ownership. The best–worst scaling technique shows that Japanese citizens prefer to maintain a sanitary environment, followed by the prevention of zoonotic diseases. Although the ranking of sanitary environmental management does not depend on cat ownership, the ranking of the other goals differs depending on cat ownership. The findings highlight the importance of strategic message framing and its prioritization in encouraging public support for invasive species management.

Impacts and management of unowned and owned cats at a seabird colony on Reunion Island (Western Indian Ocean)

Impacts and management of unowned and owned cats at a seabird colony on Reunion Island (Western Indian Ocean)

How Serious Are Health-Related Welfare Problems in Unowned Unsocialised Domestic Cats? A Study from Denmark Based on 598 Necropsies.

Simple SummaryDomestic cats are very popular companion animals, but a significant number are ownerless. These are either socialised or unsocialised. The former can be re-homed. Unsocialised domestic cats, on the other hand, are difficult to handle and fear humans. Therefore, rehoming them is challenging. Unowned unsocialised cats are seen by many people as a nuisance, a hazard to human and animal health, and a threat to biodiversity. However, others have concerns about their welfare, although our knowledge of how well these cats actually cope is very limited. To remedy this, we studied the corpses of 598 unsocialised cats euthanised in Denmark in 2019 by two cat welfare organisations. Our findings reveal that unsocialised cats in Denmark face only a moderate load of health-related welfare problems, even in comparison with owned cats. So, although there may be other reasons to euthanise unsocialised cats, this practice may, in a place like Denmark, be difficult to justify by pointing to the welfare needs of the cats.Free ranging unsocialised domestic cats are widely believed to suffer from a high load of welfare problems. We assessed the validity of this belief by performing necropsies on the corpses of 598 unsocialised cats, originating from all parts of Denmark, that had been euthanised by two Danish cat welfare organisations. We selected a number of variables for health-related cat welfare that could be assessed through necropsy (e.g., gross lesions, ectoparasites and body condition) or by laboratory analysis (e.g., infection with feline immunodeficiency virus (FIV), and by feline leukaemia virus (FeLV)). Each finding was classified as having either a major or minor welfare impact on the cat. More than 83% of the cats had no major finding, and 54% had no finding indicating a welfare issue at all. More than 83% of the cats had a body condition within normal range. Only 0.3% were emaciated. The most common finding was infestation with ectoparasites, with 15.9% infected with lice, 12.3% with fleas, 4.7% with ticks, and 6.7% with ear mites. FIV and FeLV were detected in 9.2% and 1.2% of the cases, respectively. The most common lesion related to the cats’ teeth. Overall, unsocialised cats in Denmark have a moderate level of health-related welfare problems.

Estimated number of birds killed by domestic cats in Colombia

Wildlife mortality caused by domestic cats is evident where free-roaming house cats are present in the tropical Andes region, a phenomenon for which there is a lack of scientific reports. Our goal is to present plausible range estimates of the potential avoidable number of birds killed by domestic cats in Colombia. We calculated estimates of the number of birds killed as the product of the number of cats, the proportion of cats with at least some outdoor access, the proportion of cats that hunt wildlife, the annual predation probability, and adjustments for estimates of total prey killed by cats. We extracted such data not only from public records, but also from a citizen science study, for which we circulated a questionnaire to examine cat owners’ attitudes toward the impact of domestic cats on wildlife during the 2020 and 2021 COVID-19 lockdowns in Colombia. We estimated that three to 12 million birds are killed annually by domestic cats in urban and suburban areas. In addition, we estimated that cats kill eight to 29 million vertebrate fauna in the Andes of Colombia. The total kill estimate provides a first figure on the magnitude of the impact of an anthropogenic cause of wildlife mortality for Colombia. These estimates would be more rigorous if the unowned or feral cat population size in Colombia was better known. Because most pet cats in Colombia roam outdoors without supervision and their population is growing, they pose an increasing threat to wildlife. Intervention is urgent to mitigate bird mortality by domestic cats.

Human influences shape the first spatially explicit national estimate of urban unowned cat abundance

Globally, unowned cats are a common element of urban landscapes, and the focus of diverse fields of study due to welfare, conservation and public health concerns. However, their abundance and distribution are poorly understood at large spatial scales. Here, we use an Integrated Abundance Model to counter biases that are inherent in public records of unowned cat sightings to assess important drivers of their abundance from 162 sites across five urban towns and cities in England. We demonstrate that deprivation indices and human population densities contribute to the number of unowned cats. We provide the first spatially explicit estimates of expected distributions and abundance of unowned cats across a national scale and estimate the total UK urban unowned cat population to be 247,429 (95% credible interval: 157,153 to 365,793). Our results provide a new baseline and approach for studies on unowned cats and links to the importance of human-mediated effects.

Dynamics and epidemiology of Toxoplasma gondii oocyst shedding in domestic and wild felids.

Oocyst shedding in domestic and wild felids is a critical yet understudied topic in Toxoplasma gondii ecology and epidemiology that shapes human and animal disease burden. We synthesized published literature dating from the discovery of felids as the definitive hosts of T.gondii in the 1960s through March 2021 to examine shedding prevalence, oocyst genotypes, and risk factors for shedding. Oocyst shedding prevalence in many geographic regions exceeded the commonly accepted 1% reported for domestic cats; crude prevalence from cross-sectional field studies of domestic cat shedding ranged from 0% in Australia to 18.8% in Africa, with greater variation in reports of oocyst shedding in free-ranging, wild felids. Shedding in wild felid species has primarily been described in captive animals, with attempted detection of oocyst shedding reported in at least 31 species. Differences in lifestyle and diet play an important role in explaining shedding variation between free-ranging unowned domestic cats, owned domestic cats and wild felids. Additional risk factors for shedding include the route of infection, diet, age and immune status of the host. It is widely reported that cats only shed oocysts after initial infection with T.gondii, but experimental studies have shown that repeat oocyst shedding can occur. Factors associated with repeat shedding are common amongst free-ranging felids (domestic and wild), which are more likely to eat infected prey, be exposed to diverse T.gondii genotypes, and have coinfections with other parasites. Repeat shedding events could play a significant yet currently ignored role in shaping environmental oocyst loading with implications for human and animal exposure. Oocyst presence in the environment is closely linked to climate variables such as temperature and precipitation, so in quantifying risk of exposure, it is important to consider the burden of T.gondii oocysts that can accumulate over time in diverse environmental matrices and sites, as well as the spatial heterogeneity of free-ranging cat populations. Key directions for future research include investigating oocyst shedding in under-sampled regions, genotyping of oocysts detected in faeces and longitudinal studies of oocyst shedding in free-ranging felids.

Domestic Cat Abundance and Activity Across a Residential Land Use Gradient

Free-ranging domestic cats are a detriment to wildlife and humans by preying on native species and transmitting disease. As a result, removing free-ranging cats from the landscape has become a conservation and public health priority. Estimating cat population size with an unbiased sampling design, however, especially in human-dominated areas, is logistically challenging and rarely done. The lack of robust cat population sampling limits our understanding of where cats pose risks, which is important for evaluating management strategies, such as trap-remove or trap-neuter-return. We hypothesized that cat abundance and activity both depend on human land use and demographics. Using a network of sites participating in a community science program, we conducted transect and camera trap surveys to test predictions of cat population abundance and activity across a gradient of residential land use intensity. Both sampling methods determined that cat abundance was greatest in areas with intermediate human population density and lower educational attainment. Transect data also provided evidence that cat abundance was greatest at intermediate levels of impervious surface cover (e.g., road and buildings), while data from camera traps also showed that cat abundance was positively associated with household income. Using counts of cats observed on cameras, we found that the timing of cat activity varied depending on the degree of urban intensity. Cats were more strictly nocturnal in medium and high intensity residential land-use areas, possibly because a greater proportion of these cats are unowned or because they avoid human activity. These results suggest that transect surveys conducted during the day may undercount cats in urban environments where unowned free-ranging cats predominate. Taken together, our results highlight the importance of incorporating human demographics, land use patterns, and urban context in estimating the abundance of free-ranging cats to better inform management decisions and improve conservation outcomes.

Counting Cats: The integration of expert and citizen science data for unbiased inference of population abundance.

Free‐roaming animal populations are hard to count, and professional experts are a limited resource. There is vast untapped potential in the data collected by nonprofessional scientists who volunteer their time to population monitoring, but citizen science (CS) raises concerns around data quality and biases. A particular concern in abundance modeling is the presence of false positives that can occur due to misidentification of nontarget species. Here, we introduce Integrated Abundance Models (IAMs) that integrate citizen and expert data to allow robust inference of population abundance meanwhile accounting for biases caused by misidentification. We used simulation experiments to confirm that IAMs successfully remove the inflation of abundance estimates caused by false‐positive detections and can provide accurate estimates of both bias and abundance. We illustrate the approach with a case study on unowned domestic cats, which are commonly confused with owned, and infer their abundance by analyzing a combination of CS data and expert data. Our case study finds that relying on CS data alone, either through simple summation or via traditional modeling approaches, can vastly inflate abundance estimates. IAMs provide an adaptable framework, increasing the opportunity for further development of the approach, tailoring to specific systems and robust use of CS data.

IMPORTANCE OF ASCARIDIOSIS CONCERNING HUMAN AND ANIMAL HEALTH, PRESENT CONDITION AND SOLUTION PROPOSALS IN TURKEY AND THE WORLD

Toxocariasis is a zoonotic parasitic infection, affecting millions of people and animals, commonly occurred, in the world. According to the seroprevalence studies, it is seen that exposure to this parasite is highly common in children living in temperate zones in the world. The geographic distribution of Toxocara canis is continuously expanded as a result of human and animal movements with global warming. Uncontrolled increase of human and animal populations in urban areas raises the importance of toxocariasis. Owned and unowned cats and dogs not administered treatment and wild animals create infection source for humans and other paratenic hosts by causing environmental contamination with eggs. Paratenic hosts like rodents, birds, and invertebrate animals play an important role in the spreading of the ascarid eggs. Infection in humans occurs in the result of consumption of larvae in the tissues of paratenic hosts (chicken, rabbit, pig and ruminants), drinking of dirty water, and close contact with contaminated soil and pet animals. Depending on these conditions stated, in the context of this review, concise knowledge was presented about the prevalence data in humans and animals of ascaridiosis in Turkey and the world, diagnosis, treatment and prevention measures.

Nine ways to score nine lives – identifying appropriate methods to age domestic cats (Felis catus)

AbstractAccurate determination of chronological age for cats (Felis catus) permits assessment of age at reproduction and growth measures, whilst understanding survivorship enables modelling of population dynamics underpinning many management questions. At present, the relative accuracy of different measures has not been compared, especially in relation to ageing live cats, where options are more limited. We tested relationships between nine ageing methods using a large database of 384 unowned, free‐roaming cats culled as part of wildlife conservation and unowned cat management. Cat heads were cleaned and scored for tooth eruption, development of the canines (root closure, length and width; proportion of pulp determined by radiography), canine tooth cementum lines, tooth wear (canine tip sharpness and breakage, or absence of the P2), diastema distance and closure of two cranial sutures. Tooth eruption is informative for cats up to about 8 months of age and closure of the canine root up to 12 months. In adults with closed‐rooted canine teeth, only the cementum lines and cranial sutures varied; these two sets of measures were strongly correlated. We conclude by developing a predictive table for ageing cat specimens using tooth and skull features. Animals can be aged reliably over the lifespan of the animal from cadaver material, potentially adding valuable information to ecological studies where cats are culled. However, there is no way to reliably age live cats over approximately 8 months of age in the field, after which time full adult dentition is established. Similarly, radiography (to determine pulp volume) has limited use as an ageing tool for cats older than 1–2 years of age. This reduces the number of potential applications for live cats, including, for example, ageing unowned cats in trap–neuter–release programmes.

Free-ranging domestic cat abundance and sterilization percentage following five years of a trap–neuter–return program

Increasing free-ranging cat populations are a cause of concern for wildlife management and biodiversity conservation. Cats carry and transmit multiple diseases, annually depredate billions of birds and mammals in the mainland United States, and have caused extinctions and declines of wildlife populations worldwide. Trap–neuter–return (TNR) efforts, which entail trapping, sterilizing and releasing unowned free-ranging cats with the goal of reducing populations, have been implemented globally despite limited evidence of their ability to reduce cat numbers. To assess the effectiveness of a TNR program initiated in 2013 in Stillwater, Oklahoma, USA, we used trail cameras at 15 locations to estimate changes in cat abundance and the percentage of ear-tipped (i.e. sterilized) individuals between 2014 and 2018. We reviewed photographs to identify individual cats, and after accounting for detectability with mark–resight analyses, we estimated a non-significant decrease in abundance from 62 to 48 total cats across sampled locations. In 2018, approximately 27% of cats were ear-tipped compared to 0% in 2014, yet this percentage remains far below estimated sterilization levels needed for TNR to reduce unowned cat populations. Although additional long-term monitoring is needed, our results suggest that TNR conducted at its current intensity is unlikely to reduce Stillwater's cat population. Our research adds further evidence to the growing body of scientific literature indicating that TNR is ineffective in reducing cat populations.

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

Abstract 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.

A shift towards early-age desexing of cats under veterinary care in Australia

The global problem of unowned domestic cats, driven by their phenomenal reproductive success, carries significant economic, animal welfare and biodiversity costs. Desexing owned cats prior to puberty prevents unwanted litters that contribute to unowned cat populations. The prevalence and predictors of desexing, and the age at which surgery was carried out were investigated using anonymized electronic patient records in the VetCompass Australia database of cats presented to veterinary practices. Of 52,941 cats born between 2010 and 2017, 83.6% were desexed. Among 7463 desexed females, 21.5% had been desexed by 4 months of age, 59.8% by 6 months and 85.4% by 1 year. Sex, breed, location and socioeconomic indices significantly influenced desexing status and age at surgery. Cats born between 2010 and 2017 had greater odds of being desexed than cats born between 1995and 2009 at each age cut-off (≤ 4 months [OR 1.76, CI95 1.58–1.97], ≤ 6 months [OR 1.50, CI95 1.38–1.62] and ≤ 1 year [OR 2.33, CI95 2.11–2.57] p < 0.001). Most cats presented to veterinarians in Australia are desexed. Compared with cats born before 2010, cats born later are significantly younger at desexing but, even so, many cats would have reached sexual maturity before surgery. These findings will inform the design of front-line strategies promoting prepubertal desexing and they demonstrate, for the first time, a shift towards desexing younger cats.

Estimates of wildlife killed by free-ranging cats in China

Throughout much of the world, growing populations of free-ranging domestic cats pose an increasingly serious threat to biodiversity. However, no study has estimated the magnitude of wildlife mortality caused by cats in China, one of the largest and most biodiverse nations on earth. We used a novel, survey questionnaire-based approach to estimate annual predation on wildlife by cats in China; we separately considered predation rates in urban and rural areas and by both owned free-ranging cats and unowned cats (e.g., feral and semi-feral cats including those associated with feeding and trap-neuter-return (TNR) activities). Using statistical simulations based on 2187 questionnaire responses that included direct observations of prey returns to owners and predation events by unowned cats, we estimate that the minimum annual amount of predation by all free-ranging cats in China is: 1.61-4.95 billion invertebrates, 1.61 -3.58 billion fishes, 1.13-3.82 billion amphibians, 1.48-4.31 billion reptiles, 2.69-5.52 billion birds, and 3.61-9.80 billion mammals. Thus, we show that free-ranging cats cause a tremendous death toll that may be profoundly impacting China’s wildlife populations and biodiversity. Our results indicate that there is an urgent need for increased research into the impacts of cats on wildlife in China, and for management and policy that reduces numbers of free-ranging cats and thus mitigates their harmful effects on China’s wildlife.

Reply to Wolf et al.: Why Trap-Neuter-Return (TNR) Is Not an Ethical Solution for Stray Cat Management.

Simple SummaryWe provide a rebuttal to Wolf et al. (2019), outlining biological, ethical, and economic flaws in their argument that Trap-Neuter-Return (TNR) is an ethical solution for stray cat management. We contend that suppression of supplementary feeding of stray cats accompanied by proactive adoption or prompt euthanasia is more effective, humane, and economical.We critique the recent article by Wolf et al. (2019) that claims scientific merit for reducing the number of stray cats in Australia through Trap-Neuter-Return (TNR) programs, and then we provide an inventory of biological, welfare, and economic reasons why TNR is less successful than adoption and euthanasia for managing unowned cats. Like Crawford et al. (2019) and multiple other comprehensive and unbiased Australian and international scientific reviews, we refute the idea that returning neutered unowned cats to stray populations has any valid role in responsible, ethical, affordable, and effective cat management, or in wildlife conservation. The main purported objective of TNR proponents along with animal welfare, human health, and wildlife advocacy stakeholders is to reduce the number of unhomed cats. We contend that cessation of provisioning unowned cats with food is the most effective approach to achieve this objective. We also present evidence from the Brisbane City Council that informed cat management policy, advocacy, and laws, backed up by responsible rehoming or prompt ethical euthanasia, are together effective at reducing the stray cat problem.

Contrasting practices and opinions of UK-based veterinary surgeons around neutering cats at four months old

BackgroundMany cats in the UK are not neutered before reaching potential breeding age. The purpose of this investigation was to understand the prevalence of veterinarians’ behaviours around neutering cats at...

Evidence for Citation Networks in Studies of Free-Roaming Cats: A Case Study Using Literature on Trap–Neuter–Return (TNR)

Simple SummaryAll aspects of an argument need to be evaluated in evidence-based scientific pursuit to prevent the development of self-reinforcing cohorts of studies through the cross-referencing of selected subsets of studies (citation bias). Controling populations of unowned cats using Trap–Neuter–Return and its variants (hereafter TNR) is an example of how a scientific topic develops and is communicated academically and publicly. We found 145 TNR publications between 2002–2019, with the last two years seeing a rapid increase in studies. Publication clusters occur, focusing on: population control, interactions with wildlife, disease transmission (including implications for pet cats, wildlife and humans), free-roaming cats, and feral and domestic cat management. A quarter of all studies were published in Open Access formats, which have the highest potential social impact because they are free to download, share and read. While it is encouraging that diverse views are expressed, the development of clusters of introspective topics risks reduced dialogue between groups of authors with differing views. Journal editors could encourage exchanges between groups by choosing reviewers from different camps to assess manuscripts and by asking authors to acknowledge alternative views.Trap–Neuter–Return and its variants (hereafter TNR) aims to control unowned cat populations. Papers on this topic form a useful case study of how how an area of literature grows, papers become influential, and citation networks form, influencing future study as well as public perceptions of the science. We analysed 145 TNR studies published 2002–2019. Common topics, identified by frequently used language, were population control, interactions with wildlife, disease transmission (including implications for pets, wildlife and humans), free-roaming cats, and feral and domestic cat management. One or more papers on each of these topics was judged influential because of high citations overall, high average citations/year, or frequent mentions in social media. Open Access papers were more influential in social media, raising greater public awareness than studies published in journals that were less accessible. While divergent views exist on a range of topics, the network analysis of the TNR literature indicated potential for forming self-reinforcing groups of authors. While it is encouraging that diverse views are expressed, there is a risk of reduced dialogue interactions between groups, potentially constraining dialogue to refine arguments, share information, or plan research. Journal editors could encourage communication by choosing reviewers from different camps to assess manuscripts and by asking authors to acknowledge alternative views.