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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). [ABSTRACT FROM AUTHOR]

The rather limited human ability to understand animal vision and visual signalling has frequently clouded our expectations concerning the visual abilities of other animals. But there are multiple reasons to suspect that visual signalling is more widely employed by animals than previously thought. Because visibility of visual marks depends on the background in which they are seen, species spending most of their time living in dark conditions (e.g., in forests and/or having crepuscular and nocturnal habits) may rely on bright signals to enhance visual display. Here, as a result of experimental manipulations, we present, for the first time ever, evidence supporting the use of a new channel of intraspecific communication by a mammal species, i.e., brown bear Ursus arctos adult males relying on visual marks during mating. Bear reactions to our manipulation suggest that visual signalling could represent a widely overlooked mechanism in mammal communication, which may be more broadly employed than was previously thought. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Abstract: Sarcoptic mange, a parasitic skin infection caused by the burrowing mite Sarcoptes scabiei, has been reported in over 100 mammals, including humans. In endangered species, mange causes conservation concerns because it may decimate isolated populations and contribute to extinction. The Iberian Peninsula still maintains one of the largest wolf (Canis lupus) populations in Europe. In Iberia, sarcoptic mange is endemic in red foxes (Vulpes vulpes) and the first confirmed wolf mange cases were recently reported. However, knowledge on S. scabiei in wolves is scarce because of the sampling difficulties inherent to research on scarce species. In order to describe wolf mange epidemiology and to infer conservation implications, this study combined traditional laboratory techniques with the revision of wolf carcass pictures taken by field biologists and original information obtained by camera trapping. A total of 125 necropsies and 8783 camera-trap days allowed insights into wolf mange epidemiology between 2003 and 2010. Living Sarcoptes mites were detected in 19% of the fresh carcasses. Alopecic (delayed) type IV hypersensitive response reactions were observed, while parakeratotic lesions were infrequent. The number of mites isolated per wolf ranged from 1 to 78, and had a negative correlation with the percentage of alopecic skin. No effect by sex on mange prevalence was found. Yearlings showed a lower probability to present mange-compatible lesions than pups or adults. Wolves with mange-compatible lesions had a lower kidney fat index than apparently healthy ones. ELISA testing of 88 sera yielded an antibody prevalence of 20%. Photo-trapping recorded mange-compatible lesions since 2003 with a peak in 2008. The percentage of wolves with mange-compatible lesions registered in camera-traps during 1 year correlated with the percentage of red foxes with lesions in the previous year. This is the first large survey on sarcoptic mange in the Iberian wolf. Necropsy data, with alopecia as the main feature and a slight effect on body condition, and trends derived from camera trapping coincided in showing a rather low prevalence and an apparently stable situation of the disease and its host, suggesting that this parasite is currently not a major threat for this wolf population. However, more information is needed in order to assess the effect of mange on aspects such as pup survival. [Copyright &y& Elsevier]