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Infanticide is a significant evolutionary force influencing carnivore behaviours, as it is one of the primary contributors to offspring mortality. Female multimale mating, which creates paternal uncertainty, is known to reduce infanticide. We propose that two crucial steps are needed for this strategy to work in solitary species like brown bears, Ursus arctos. First, after mating, females should choose dens within their mating area (step 1), boosting the chances of encountering potential fathers of cub(s) after den emergence in spring. However, the efficacy of this strategy hinges on males' fidelity to the same mating areas from one year to the next (step 2). Our study confirmed that pregnant females consistently selected dens within their mating areas, with significant overlap (around 90%) between areas used by females with cubs and their mating zones. Males also demonstrated fidelity (over 65%) to mating areas over 2 consecutive years. Infanticide significantly shapes the sociospatial ecology of female brown bears, a phenomenon that can carry nutritional costs for females with cubs, and influence settlement patterns near human shields to increase reproductive success. Additionally, in hunted populations, removing resident males can trigger an influx of potentially infanticidal bears from elsewhere.

Las marcas que los osos dejan en los árboles con sus mordiscos y arañazos, en concreto los machos adultos en época de celo, podrían ser una forma de comunicación nunca antes detectada en mamíferos carnívoros. Un estudio realizado en la Cordillera Cantábrica confirma la relevancia de estas señales visuales para los osos. Para comunicarse con sus congéneres en diferentes contextos, y por una variedad de razones, los animales usan señales, a veces simples y otras más elaboradas. En ocasiones estas señales son simplemente más difíciles de comprender, porque no son siempre tan evidentes para nosotros, los humanos. El estudio de la comunicación animal es uno de los campos de investigación más complejos. Los científicos hemos creído durante mucho tiempo que diversas especies animales, en particular aves y mamíferos crepusculares y nocturnos, empleaban vías de comunicación basadas exclusivamente en el sonido (como el aullido de los lobos) y las señales químicas (como heces, orina y secreciones de glándulas corporales). Pero como destaca el zoológo Eric Warrant, "nuestra propia capacidad bastante limitada, junto con sentimientos injustificados de superioridad sensorial, han nublado nuestras expectativas con respecto al poder de la comunicación visual de otros animales".

Climate and land use change can affect biodiversity in different ways, e.g., determining habitat loss, altering reproduction periods or disrupting biotic interactions. Here, we investigate the effects of climate and land use change on the spatial distribution of two semi-aquatic mammals, the Pyrenean desman (Galemys pyrenaicus) and the Eurasian otter (Lutra lutra). We first modeled the current potential distribution of the desman and the otter in the Iberian Peninsula, considering topographic, climatic and land use variables. Second, we predicted their potential distribution in 2050 under climate and land use change scenarios. We calculated the percentage of range gain/loss and shift predicted for the two species under such scenarios and quantified the present and future spatial overlap between the two species distribution. Irrespective of the scenario, desman models show loss of suitable habitat, whereas the otter will undergo an opposite trend. Aside from a preponderant habitat loss, the desman is predicted to increase its spatial overlap with otter range under the optimistic scenarios, potentially meaning it will face an exacerbated predation by otters. The potential increase of both habitat loss and otters’ predation might represent a major threat for the desman, which may affect the long-term persistence of this endemic species in the Iberian Peninsula.

Intraspecific communication in mammals is well-documented but generally restricted to chemical and acoustic signaling. However, other overlooked channels, such as visual signaling, may be used to communicate among conspecifics. Here, by using experimental manipulations together with camera traps on 13 brown bear (Ursus arctos) rubbing trees in the Cantabrian Mountains (northwestern Spain), we document detailed temporal patterns and behavioral aspects of a recently discovered novel communication channel for this species, visual signaling through the trunk debarking of focal trees. Video footage showed that visual marking is a sex-, age-, and time-specific means of communication in brown bears, being performed exclusively by adult males during the mating season (mainly April–June in the study area). Trunk debarking was always associated with chemical marking and was never an isolated behavior, suggesting that visual and chemical signals might be complementary. Visual and chemical marks may provide different information; for example, visual marks could be an indicator of individual size and, thus, the dominance status of adult males looking for mating opportunities. This is the first time that evidence is provided showing that visual signaling in a large carnivore is exclusive to a specific class of individuals (adult males) and linked to reproductive needs only. Bear visual signaling not only represents an advance in our comprehension of animal communication but may also serve to easily locate the mating areas of mammals, which are crucial for large carnivore species, such as the brown bear, that frequently need specific and urgent plans for conservation and management.

Patches of color may be used to communicate to conspecifics, mainly in species showing uniform coloration, and may (a) help individuals maintain visual contact, such as between mothers and their young; (b) function as signals of subordination or to frighten rivals; (c) warn conspecifics of approaching predators; and/or (d) signal reproductive condition, health, or genetic quality to potential mates. Intraspecific communication represents one of the major evolutionary forces responsible for the coloration of body parts, but the meaning of many of these signals is still unclear. One of the first steps to understanding whether fur marks have a role in social communication is to understand whether such body patches are stable over time (i.e., whether they represent a unique visual signature for every individual). During the period 1999–2021, we recorded yearly pictures of 7 female (mean no. of monitoring years per bear = 13.6, standard deviation [SD] = 4.6; range = 9–22 yr) and 6 male (mean no. of monitoring years per bear = 9.3, SD = 4.3; range = 5–15 yr) brown bears (Ursus arctos) in the Cantabrian Mountains (NW Spain). We show that body mark shapes are stable over time and, because of their uniqueness, might represent a distinctive signature of individuals. Brown bear body marks may act as multicomponent signals, where different features of a given mark may inform about different aspects of the bearer or act as back-ups. For example, a quality-signaling capacity does not preclude the same mark from being used in other functions at the same time, such as individual recognition. Noninvasive techniques helpful for identifying individuals have been developed for estimating population size, reproductive rates, and the survival of several carnivore species. Fur marks that are stable over time can thus be useful in field research (e.g., body marks that are persistent and do not vary over time are an important tool in longitudinal photographic capture–recapture studies).

Large carnivores have long fascinated human societies and have profound influences on ecosystems. However, their conservation represents one of the greatest challenges of our time, particularly where attacks on humans occur. Where human recreational and/or livelihood activities overlap with large carnivore ranges, conflicts can become particularly serious. Two different scenarios are responsible for such overlap: In some regions of the world, increasing human populations lead to extended encroachment into large carnivore ranges, which are subject to increasing contraction, fragmentation, and degradation. In other regions, human and large carnivore populations are expanding, thus exacerbating conflicts, especially in those areas where these species were extirpated and are now returning. We thus face the problem of learning how to live with species that can pose serious threats to humans. We collected a total of 5,440 large carnivore (Felidae, Canidae, and Ursidae; 12 species) attacks worldwide between 1950 and 2019. The number of reported attacks increased over time, especially in lower-income countries. Most attacks (68%) resulted in human injuries, whereas 32% were fatal. Although attack scenarios varied greatly within and among species, as well as in different areas of the world, factors triggering large carnivore attacks on humans largely depend on the socioeconomic context, with people being at risk mainly during recreational activities in high-income countries and during livelihood activities in low-income countries. The specific combination of local socioeconomic and ecological factors is thus a risky mix triggering large carnivore attacks on humans, whose circumstances and frequencies cannot only be ascribed to the animal species. This also implies that effective measures to reduce large carnivore attacks must also consider the diverse local ecological and social contexts.

Moonlight plays a significant role in prey–predator relationships. At full moon, predators' hunting success and activity rates generally increase. Even though the analysis of facultative carnivore movement patterns can improve our knowledge of how moonlight can change the behaviour of such a group of species with diverse ecological needs, few studies have been conducted with facultative carnivores and none with telemetric data. Here, we studied whether moonlight influences brown bear, Ursus arctos, movement behaviours. By analysing data collected from 2002 to 2014 for 71 collared individuals inhabiting Finland and Russian Karelia, we found that some internal and external factors are influencing brown bear movement patterns. In particular, this facultative carnivore moves more slowly and over shorter distances during hyperphagia periods than during the mating season. However, moonlight does not affect brown bear movements. Although brown bears are large carnivores, they are opportunistic omnivores with a high fruit diet and, therefore, the prey–predator relationships that are behind the dependence of carnivores on moonlight seem to be weaker than in obligate carnivores.

Many animals make behavioural changes to cope with winter conditions, being gregariousness a common strategy. Several factors have been invoked to explain why gregariousness may evolve during winter, with individuals coming together and separating as they trade off the different costs and benefits of living in groups. These trade-offs may, however, change over space and time as a response to varying environmental conditions. Despite its importance, little is known about the factors triggering gregarious behaviour during winter and its change in response to variation in weather conditions is poorly documented. Here, we aimed at quantifying large-scale patterns in wintering associations over 23 years of the white-winged snowfinch Montifringilla nivalis nivalis. We found that individuals gather in larger groups at sites with harsh wintering conditions. Individuals at colder sites reunite later and separate earlier in the season than at warmer sites. However, the magnitude and phenology of wintering associations are ruled by changes in weather conditions. When the temperature increased or the levels of precipitation decreased, group size substantially decreased, and individuals stayed united in groups for a shorter time. These results shed light on factors driving gregariousness and points to shifting winter climate as an important factor influencing this behaviour.

Ongoing climate change can shift organism phenology in ways that vary depending on species, habitats and climate factors studied. To probe for large-scale patterns in associated phenological change, we use 70,709 observations from six decades of systematic monitoring across the former Union of Soviet Socialist Republics. Among 110 phenological events related to plants, birds, insects, amphibians and fungi, we find a mosaic of change, defying simple predictions of earlier springs, later autumns and stronger changes at higher latitudes and elevations. Site mean temperature emerged as a strong predictor of local phenology, but the magnitude and direction of change varied with trophic level and the relative timing of an event. Beyond temperature-associated variation, we uncover high variation among both sites and years, with some sites being characterized by disproportionately long seasons and others by short ones. Our findings emphasize concerns regarding ecosystem integrity and highlight the difficulty of predicting climate change outcomes.

Human–wildlife conflicts sometimes involve bold animals that do not fear humans and their activities. Such behaviour is detrimental to both wildlife and people and may lead to conflicts, which can be especially serious for large carnivores. Like most wildlife, these species have adapted to live in highly humanized landscapes by adopting human avoidance behaviours. However, bold individuals exist, which represent a main cause of conflicts, public fear and negative attitudes, that greatly influence management and conservation actions. Although costly decisions are constantly made to deal with such individuals, evidence-based knowledge of their behaviour, that is how and when they move, especially in relation to human activities, is lacking. We analysed telemetry data of brown bears (Ursus arctos) that were GPS-collared across Slovenia and Trentino (Italy) to explore spatial behaviour and rhythms of activity of bears that were identified as bold by managers and to assess if and how their behaviour differs from that of their ‘non-bold’ conspecifics (hereafter, control individuals). Because other factors such as sex and age of the bear, season, daytime and region may affect behaviour, we also included these variables in our analyses. On one hand, bold bears were more active at the daytime and used open areas considerably more often than control bears. On the other hand, although differences in distance to settlements and roads, movement rates and daily home ranges were also found, they were not as pronounced as expected. Instead, other factors were found to affect bear behaviour and, most importantly, we found strong inter-individual differences in all behaviours. Such results suggest that, although bold bears have some behavioural attributes in common that distinguish them from control bears, each individual differs from one another. Our study represents a first step towards understanding bold bears’ behaviour and provide novel evidence-based knowledge that can help to

Animal coloration is widely involved in a variety of social interactions, and mammals can convey information to conspecifics by visual signals, such as colored or contrasting body marks. The sun bear (Helarctos malayanus) has a vibrant and unusual chest mark. Here, we describe the characteristics of sun bear chest marks and their patterns of individual variation by (1) sex, (2) time, and (3) some biochemistry values related to fur pigmentation. Sun bear pictures were taken from 2009 to 2018 at the Bornean Sun Bear Conservation Centre and Free the Bears sanctuary. We hypothesize that chest marks may serve in conspecific communication and, thus, we mainly expect that (a) these marks allow for sexual recognition and, thus, they should show remarkable differences by sex; (b) marks do not change over time because their consistency allows for easier intraspecific recognition; and (c) patterns of variation may be dependent on the age and/or physical condition of an individual. The most common shapes of sun bear chest marks (n = 63 M and 108 F) were U (M = 60.3%, F = 57.4%) and V (M = 31.8%, F = 32.4%) shapes. We did not detect differences in shape patterns by sex and, over the years, chest mark shape never changed for the same bear (n = 49 individuals, 16 M and 33 F). The number of dark dots in chest marks showed large amounts of individual variation (mean ± SD = 37.7 ± 26.8 dots; range = 1–143), and the quantity of dark dots increased with bear age. The complexity of sun bear chest marks might be related to the existence of complex interactions among individuals of the same species, which may allow for recognition and evaluation of their individual characteristics, such as age and health. Experimental approaches are needed to understand the potential functions of sun bear chest marks.