Abstract Classification systems are useful tools for aggregating diseases to study them in more detail. The most widespread system for the classification of human diseases is the International Classification of Diseases (ICD); however, the ICD was designed for use in health care and fails to capture many details of zoonotic diseases as a result. We propose a framework for zoonotic disease classification which combines four known classification types (pathogen type, life cycle, transmission direction and ecosystem) into one systematic method. We chose to focus on four specific aspects to provide as broad an overview as possible of zoonoses, in order to inform the risk of transmission to humans. This framework can be applied to the zoonoses occurring in any non‐human animal species and supports the generation of systematically collected empirical data that are useful for monitoring the spatio‐temporal dynamics of zoonoses. To demonstrate the utility of our framework, we focus on six deer species that are widespread in Eurasia: red deer Cervus elaphus, roe deer Capreolus capreolus, fallow deer Dama dama, sika deer Cervus nippon, Reeves's muntjac Muntiacus reevesi and Chinese water deer Hydropotes inermis. We examined the worldwide occurrence and prevalence of zoonoses in these species through a scoping review of the literature. Altogether, 996 records of zoonotic diseases in the six wild deer species, from 431 peer‐reviewed papers, and 120 zoonotic pathogens were found. Within deer populations, the most prevalent zoonoses were bacterial, while the most prevalent life cycles were metazoonoses. We also found that the most prevalent pathogens in deer were those with hosts capable of occupying sylvatic, peridomestic and domestic ecosystems. Baseline data generated using our framework method can provide important starting points for making projections of human disease risk, assisting wildlife managers and policy‐makers in making wildlife management decisions, and assisting experts in the development of disease‐monitoring and management plans.

Abstract The sex ratio of sexually reproducing animal species is usually close to 1:1 and could be influenced by both parents. Deviations from this ratio occur in nature and can have an adaptive role. Although there are several evolutionary hypotheses explaining this bias, there is a significant lack of knowledge of the mechanisms of sex ratio facultative adjustments. While maternal effects are relatively well studied, the paternal effects on the primary sex ratio remain elusive. This review aims to assemble and summarise the knowledge of male control in sex allocation. In particular, we focused on identifying possible mechanisms through which the adjustment could be achieved at pre‐, peri‐ and post‐fertilisation levels. A systematic literature review was performed. We selected 59 articles that provided a potential proximal explanation of observed offspring sex ratio skews for which mammalian males might be responsible. We outlined potential physiological and genetic mechanisms of male‐driven sex allocation operating in male germ cells and zygote stage in mammals. However, most of the proposed hypotheses of how males can bias the offspring sex ratio concern mostly the production of unequal numbers of Y‐ and X‐chromosome‐bearing spermatozoa, and their differences in morphology and physiology. As males possess a wide range of mechanisms to effectively alter the sex ratio of their offspring, they can play a significant role in this phenomenon and should be studied to reduce the gap in our understanding of their role in sex allocation in comparison to the role of females. More empirical studies on different mammalian models are needed to fully characterise the trends of the adjustment. Predicting the sex ratio of the progeny is of great importance, not only in animal husbandry but also for the conservation of endangered species.

Abstract Since the 1990s, the number of lions (Panthera leo) has declined by about 43% across African range states. Reliable lion population estimates can contribute to effective management and inform local and international conservation policies. Though many survey methods have been used to estimate lion abundance, an assessment of their usefulness and effectiveness is lacking. We reviewed and identified available methods used to estimate lion populations, then investigated their feasibility, cost‐effectiveness and suitability to achieve primary objectives. We identified 12 methods in two categories: direct (minimum counts, call‐in surveys, capture–recapture, opportunistic sightings, remote cameras, distance‐based and aerial counts) and indirect (track counts, secondary information, prey‐based, genetic samples and roar counts). We identified 48 studies (57%) in which lion population estimation was not repeatable. Additionally, 38% did not provide any measure of precision. About 28% of the studies were conducted specifically for management purposes, while remaining studies focused on population estimates and dynamics. Because data from these studies have influenced local management and global lion conservation policies, we recommend basing future policies and management on repeatable, precise and accurate population estimates supported by appropriate and cost‐effective experimental designs. In most cases, these estimates are obtained through actual lion counts derived from direct observation methods including call‐in, capture–recapture and remote camera surveys or through reliable animal signs such as genetic samples.

Abstract Antarctic fur seals (Arctocephalus gazella) are an iconic marine mammal, an important component of Antarctic ecosystems, and a key indicator species for regional fisheries management. Recent studies have demonstrated Arctocephalus gazella is composed of at least four distinct subpopulations, including one breeding on the South Shetland Islands. These South Shetland Antarctic fur seals (SSAFS) are the highest latitude population of otariids in the world. As such, this subpopulation faces a unique array of environmental and ecological challenges, harbours a disproportionately large reservoir of genetic diversity for the species, and has experienced catastrophic population decline in the last 15 years (2008–2023). We review the array of current and potential threats to the successful recovery of SSAFS. If decision makers wish to promote resilience and support a robust population of this species with future recovery potential, actions are needed to address threats ranging from uncertain to critical, including debris entanglement, climate change, incidental mortality, and resource competition with the krill fishery. In particular, the risks associated with overlap in the spatial and temporal distribution of the young of the year and the krill fishery should be addressed carefully. There is an urgent need for updated population estimates for all Antarctic fur seal subpopulations, analysis on the population viability of the SSAFS, and further characterising summer and winter foraging behaviours to better inform potential conservation actions.

Abstract Carnivora species present specialisations for carnivorous diet, although their dietary spectrum is variable: some are strictly carnivorous, others feed mostly on plants. Knowledge about Carnivora feeding habits and resource use patterns is the basis for understanding ecological dynamics, including their role in ecosystems, trophic interactions and conservation. We aimed to contribute to the identification and description of the trophic guild structure of Carnivora species throughout the Neotropical Region and explore the main drivers behind their structuring. We compiled Carnivora dietary studies and evaluated trophic guild formation through network analysis, diet dissimilarity and overlapping. We investigated whether there is spatial variation in diet parameters and the role of phylogeny in trophic guild structuring. We found dietary studies for 32 species from six Carnivora families. We observed two important biases: most studies focus on large‐bodied felids and canids and were predominantly conducted in South and South‐eastern regions of South America. Additionally, it has been noted that biomes such as the Amazon and Caatinga require further research on dietary studies. The network patterns evidenced that central items in carnivorans' diet are small mammals, plants, arthropods and crustaceans. Modularity suggests grouping generalists/opportunists, marine‐based, plant‐based and two mammal‐based diets. Most opportunistic and generalist species were found within the families Canidae and Procyonidae, while felids were strictly carnivorous. Dietary parameters reveal carnivorans tend to maintain niche breadth regardless of the ecoregion, possibly by substitution of items in their diet. Finally, we observed that phylogeny is an important driver of dietary patterns, indicating that evolutionary history explains part of the habits of carnivores. Our review provides insights to identify broad‐scale patterns and guidelines for new studies.

AbstractPinniped species undergo uniquely amphibious life histories that make them valuable subjects for many domains of research. Pinniped research has often progressed hand‐in‐hand with technological frontiers of wildlife biology, and drones represent a leap forward for methods of aerial remote sensing, enabling data collection, and integration at new scales of biological importance. Drone methods and data types provide four key opportunities for wildlife surveillance that are already advancing pinniped research and management: 1) repeat and on‐demand surveillance, 2) high‐resolution coverage at large extents, 3) morphometric photogrammetry, and 4) computer vision and deep learning applications. Drone methods for pinniped research represent early stages of technological adoption and can reshape the field as they scale towards the full potential of their techniques.

Abstract Ecological interactions involving wildlife (wild mammals) and cattle Bos taurus are considered fundamental drivers of animal tuberculosis (TB) caused by Mycobacterium bovis at the wildlife–livestock interface. Despite recent insights about the role of direct and indirect interactions on TB dynamics, a mechanistic evaluation of studies addressing patterns of wildlife–cattle interaction at the global level is lacking, and the most likely factors explaining interaction rates under different epidemiological scenarios remain poorly understood. We began by reviewing the main criteria used to define a wildlife–cattle interaction relevant to Mycobacterium bovis transmission under different methodological approaches (camera‐trapping, proximity loggers and Global Positioning System collars). Secondly, we applied a generic framework to estimate and characterise interaction patterns between susceptible wildlife and cattle hosts worldwide, testing the effect of potential ecological and methodological factors on interaction rates. We synthesise two main criteria to define direct interactions and five criteria to define indirect interactions between wildlife and cattle. Using data from 31 studies, our meta‐analysis showed that wildlife–cattle direct interaction rates were low (mean = 0.03 interactions/month per species pair, range: 0.00–0.12). In contrast, indirect interaction rates were 154 times higher than the mean of direct interaction rates (mean = 4.63 interactions/month per species pair, range: 0.16–30.00). To prevent TB transmission to cattle, attention should be given to indirect interactions between wildlife and cattle in shared environments. Indirect interactions significantly increase with increasing wildlife density, which, hypothetically, could result in a higher TB transmission risk for cattle. We outline recommendations to achieve harmonised integration and comparison of results in future studies. Consolidation of knowledge in this field will contribute towards guiding control and biosecurity measures, also applicable to other infectious diseases at the wildlife, domestic species and human interfaces.

Abstract In coexisting carnivorans (Carnivora) relying on the same food resources, the dominant species imposes a cost on the inferior competitor by limiting its foraging ability. Tigers Panthera tigris and leopards Panthera pardus live in sympatry in most Asian countries and, because of their similar trophic niche, ‘interference competition’ may exist between these two predators. In fact, since tigers generally occupy prime habitats, leopards could be forced to roam into peripheral areas that are heavily used by humans to avoid competition, consequently increasing the risk of human‐leopard conflicts. Using information collected from the reviewed scientific literature, the purposes of this work were: 1) to assess if livestock predation by leopards increases in areas of coexistence with tigers, and 2) to characterise leopard attacks on livestock to discern the main factors involved in the human‐leopard conflict. Our findings showed that the leopard's ‘overall’ livestock predation rate (i.e. individuals taken/year) was higher in the absence of tigers than in their presence, and the same was observed for the ‘sheep and goat’ predation rate. These results confirm the leopard's tendency to take livestock and, especially, smaller prey. Conversely, the ‘cattle’ and ‘other’ predation rates were higher in the presence of tigers than in their absence, suggesting the existence of a sort of spatial segregation between predators in certain contexts. Lower levels of predation by leopards were observed on farms in which more prevention measures were used, than in those in which only one measure was implemented. We stress the importance of using proper prevention measures to mitigate human‐leopard conflicts. However, because their implementation may not be easy or economically feasible, the financial support given by carnivoran‐policy makers assumes remarkable importance to minimise the economic impact on local families and, in turn, to foster the coexistence between leopards and humans in shared landscapes.

ABSTRACT Collective decision‐making is an essential part of day‐to‐day life for group‐living animals. These decisions can be unshared (e.g. leadership) or shared (e.g. consensus). Aquatic mammals face particular challenges when making collective decisions, including a three‐dimensional habitat that can make group coordination and collective navigation a challenge. We systematically reviewed literature on decision‐making in non‐human mammals by examining the types of collective decisions observed and hypotheses used to structure analyses. Most of the current literature was centred around terrestrial species, particularly within primates and artiodactyls. There are no collective decision‐making studies on aquatic mammal species outside of cetaceans. Both unshared and shared decision‐making have been reported in whales and dolphins, with leadership found in killer whales Orcinus orca and bottlenose dolphins Tursiops sp. and consensus decisions in sperm whales Physeter macrocephalus. Five recommendations for decision‐making research include: 1) clearly delineating the temporal components of decision‐making, 2) standardising research to allow for comparisons, 3) considering both shared and unshared decision‐making, 4) analysing decision‐making across behavioural contexts, and 5) avoiding anthropomorphic terminology. Future studies of collective decision‐making will help us better understand how non‐human mammals overcome environmental and contextual challenges – particularly in the case of aquatic species such as cetaceans, which face challenges related to their aquatic environment and exhibit phenomena such as mass strandings.

ABSTRACT Mammalian carnivores (Carnivora) are crucial components of landscapes, because of both their top‐down effects on lower trophic level species and their sensitivity to bottom‐up processes, such as limited food resources (e.g. due to climate instability). To understand their functional role in Iberian ecosystems more clearly, and to define effective plans for their management and conservation, it is crucial to sum up the available regional knowledge that can inform decision‐making processes. We review bio‐ecological research on wild Iberian carnivores over 30 years (1990–2020) and identify key knowledge gaps and priority avenues for future research. Based on a systematic review of the scientific literature, we aimed to: 1) summarise current knowledge; 2) assess species and ecoregion representativeness; 3) identify key research topics addressed and those lacking investment and 4) suggest key future research priorities. We examined 920 peer‐reviewed articles involving wild Iberian mammalian carnivores, focusing on different bio‐ecological issues. We found considerable heterogeneity in the topics and species investigated, as well as in the study areas (ecoregions) explored, with a mismatch between the research priorities identified by researchers and the knowledge gaps. We suggest that future research should prioritise: 1) rear‐edge populations that are at the southwestern limits of the species' Eurasian range, thus being particularly sensitive to the increasing fragmentation and aridity of Iberian ecosystems, and that were less studied (e.g. brown bear Ursus arctos, stoat Mustela erminea, European mink Mustela lutreola and pine marten Martes martes); 2) less‐studied topics, such as morphometry and body condition, ecophysiology, and reproductive biology, all of which provide essential information for species' management and conservation and 3) specific ecoregions for which studies on species' adaptations to environmental and anthropic contexts are lacking (e.g. northern ecoregions of Iberia, Iberian conifer forests and Northwest Iberian montane forests). Our review provides the necessary background to support future research on carnivore populations in Iberia.