Over the last 70 years, introduced beavers (Castor canadensis) have been successful in establishing and modifying the landscape of southernmost Patagonia. Habitat availability and lack of large carnivorous predators have contributed to this success. The Fuegian culpeo fox (Pseudalopex culpaeus lycoides) is an endangered subspecies and the largest native predator found in Tierra del Fuego Island. The predatory behavior of a culpeo towards a beaver was studied by analyzing a video footage recovered by tourists, and consumption of beaver was documented with camera traps. An ethogram of the predatory behavior sequence was developed and true durations and percentage of time allocated to each behavior were analyzed. The “capture” and “watch” behaviors had the highest durations within the predatory sequence (61.83 and 42.61 s, respectively), while “rest” was the most frequent maintenance behavior observed (93.82 s). The culpeo may provide the only natural population control for beavers, although up to date, there is no evidence to confirm this ecological role. Based upon photos from camera traps, we confirm the occurrence of fox feeding on beavers. This is the first description of the stages of the interaction between a Fuegian culpeo fox and a North American beaver under natural conditions. We discuss the ecological implications of this interaction.

Whether right- and left-handedness are defined as a function of individual tasks or represent general categories across tasks has been long debated. However, the literature on handedness primarily concerns industrialized societies in which manual work has been extensively automated, and the majority of individuals in those countries do not use their arms and hands intensively for highly specialized tasks on an everyday basis. Thus, the question remains whether results from those countries regarding handedness are transferable to countries where the majority of individuals are still exploiting their lateralized skills. Here, we sampled 506 individuals from 143 locations on the islands of Flores and Adonara, Indonesia, to assess their hand preference for and hand performance on several tasks in order to evaluate, in a non-industrialized country, the level of manual specialization and the relevance of right- or left-handedness as general categories. Generalized-declared handedness was consistent with task-declared handedness across 10 specific tasks and with a measure of strength and a measure of skilfulness, suggesting that general handedness is a valid concept. This hand specialization for tasks is discussed in the context of intense and daily tool use in this agricultural society.

Prey must balance the conflicting demands of foraging and defensive behavior. Foraging under the threat of predation may be further complicated among species that engage in caudal autotomy, the loss of a portion of the tail at preformed breakage planes, because the tail may serve as an important energy storage organ and contribute to motility, culminating in a trade-off between foraging and predator avoidance. As a result of the advantages conferred by the presence of a tail, individuals that have recently undergone autotomy may be more motivated to forage despite elevated levels of threat indicated by predator kairomones. We used a full factorial design to evaluate the combined effects of body size, exposure to predator kairomones, and experience with autotomy on the latency to strike at Drosophila prey, number of strikes, and prey captured per strike by Allegheny Mountain dusky salamanders (Desmognathus ochrophaeus). In our study, caudal autotomy was the only significant main effect and influenced both the latency to attack prey and the number of strikes attempted. In terms of latency to attack prey, there was a significant interaction between body size and autotomy such that “small” salamanders (≤3.2 cm SVL) without tails delayed their foraging behavior. In terms of the number of strikes toward prey, there was a significant interaction between autotomy and exposure to predator kairomones such that individuals with intact tails exhibited a greater number of strikes, with the exception of the “large” (>3.2 cm SVL) salamanders, which performed fewer strikes when exposed to the snake kairomones. There was no significant effect on foraging efficiency, although the trend in the data suggests that autotomized individuals forage more efficiently. This study was designed to evaluate the confluence of factors related to size, caudal autotomy, and exposure to stimuli from predators and hints at the magnitude of caudal autotomy on antipredator decision-making. Our data suggest that despite the importance of tail tissue for energy storage, locomotion, and mating, salamanders without tails are cautious when foraging under elevated risk.

Recently, a highly invasive alien species, the zebra mussel Dreissena polymorpha, has colonized Italian aquatic ecosystems that had been previously colonized by another highly invasive alien species—the North American crayfish Procambarus clarkii. This was the first time and world region where these two species met. To evaluate the relative importance of their interactions, we studied prey selection according to its length, as well as prey choice by P. clarkii preying on D. polymorpha in the presence and absence of alternative prey—the freshwater snail Physella acuta. We followed an optimability-based approach, by first estimating the most profitable length of each mollusc and then by conducting a prey choice experiment, on which both species were provided simultaneously to a crayfish with different size combinations. Prey selection was dependent on prey length, handling time and crayfish length for both molluscs. According to our profitability estimates, snails should be more profitable than mussels in the length range 7–10 mm, while for lengths over 11.0 mm, mussels should be more profitable. The results of the prey choice experiment indicated that D. polymorpha length, P. acuta length, and the difference in profitability between the offered individuals were all relevant for the choice of one species over the other by P. clarkii. However, the overall tendency was the choice of the smallest prey, regardless of species, and the estimates of prey profitability were not useful to predict prey choice. Our study shows that D. polymorpha represents a novel prey resource for P. clarkii, even in the presence of an alternative prey, and that zebra mussels may be a preferred prey, especially small-sized individuals (5–10 mm).

Several anecdotal reports indicate that walruses (Odobenus rosmarus) occasionally attack seabirds, which potentially impacts local bird populations. However, the manner in which walruses interact with seabirds and the motivational basis of such interactions have not been investigated. Here, we describe and characterize the behaviour of wild Pacific walruses (O. r. divergens) directed at seabirds in water near the summer haulout in the Chukchi Sea. Although most walruses showed no interest in seabirds nearby, some individuals intentionally approached them both alone and in groups. A total of 74 seabird encounters for 71 individually identified walruses were registered. Behavioural analysis based on detailed observations, photography and video recording showed that the most common types of walrus behaviour toward a bird were approach by surfacing and splash, approach by surfacing and hit and attack from below. Immature individuals initiated 82% of encounters. The motivation to approach a bird was low in adult individuals, with the majority of encounters involving adults initiated by males. Walrus encounters with live birds showed a very low rate of bird kill. Encounters with dead birds were followed by further manipulations with bird carcasses, which included both the consumption of bird soft tissue and object play taking the form of drop–catch behaviour. In addition eight cases of the object-oriented play with a bird carcass in a group of walruses were observed. Object play in wild walruses is reported for the first time. Our results indicate that in seabird encounters, walruses display diverse behavioural patterns, not limited to predatory responses.

The hooded crow Corvus cornix is a west Palaearctic, solitary nesting, monogamous corvid. In the breeding season, populations are characterized by a social organization wherein breeding pairs are territorial and non-breeding individuals, called floaters, live in flocks. During a study of the breeding ecology of the hooded crow, conducted in a protected flooded area, we monitored nests with video cameras. We recorded two separate incidents when intruders attacked a female at the nest. We believe that she remained in the nest in order to prevent the strangers cannibalizing the nestlings by mantling over the brood. The spatio-temporal occurrence of these attacks suggests that the observed behaviour is intraspecific sexual aggression wherein non-breeding males mounted an immobilized female.Electronic supplementary materialThe online version of this article (doi:10.1007/s10211-015-0222-z) contains supplementary material, which is available to authorized users.

It is well established that recognition of complex acoustic signals, such as bird song, is dependent upon the temporal ordering of signal units or syntax. Much less is known about functionally analogous visual displays. The jacky dragon (Amphibolurus muricatus) is a native Australian agamid lizard with a highly stereotyped visual display made up of three discrete motor patterns. We conducted a playback experiment using high-resolution computer animations of conspecifics to test the importance of temporal order for signal efficacy. Lizards were shown three different life-sized simulated animations of conspecific differing in their skin texture and morphology signatures ranging from highly natural to abnormal. We evaluated signal recognition and assessed the relative importance of syntax and morphology. Our results showed that signal recognition is highly sensitive to syntax and this largely determines the observers’ behavioural responses. Stimuli with abnormal texture and shape were highly effective, as long as the natural order of motor patterns was preserved. Display recognition in jacky lizards hence depends upon syntax in just the same way as temporally constrained signals in other modalities.

The Olfactory system serves more than just sensory function. The detection of chemosensory cues in the environment can trigger different emotional and social responses. A recent study described a juvenile mice pheromone that suppresses sexual behavior from other adult mice, through the activation of the vomeronasal-accessory olfactory system and the medial amygdala neural pathways.

We employed global positioning system (GPS) locations of 18 marked cougars and genetic material from 68 cougars in the Southern Yellowstone Ecosystem to test our current assumptions about the social organization of this non-cooperative, solitary carnivore. We tested whether variable numbers of spatial associations over 7 years of our project could be explained by increasing numbers of wolves in the system, decreasing numbers of prey, changes in cougar density, the mean genetic relatedness between interacting individuals, or the timing of the breeding season. We documented 92 spatial associations and an additional 190 incidents of spatial overlap. Our models suggested only season influenced the number of associations in any given year, and a greater frequency of associations occurred in the breeding season. Nevertheless, the proportion of associations that were male–female (M–F) remained consistent across breeding and non-breeding seasons, suggesting M–F associations may not entirely be driven by mating opportunities; alternatively, the frequency of associations may have been driven by snow depths and the distributions of cougar prey in winter. The mean r value for female–female spatial associations was 0.087 (defined as “unrelated”) and did not significantly differ from M–F or M–M associations. In conclusion, our genetic research revealed not only matrilineal lines in the Southern Yellowstone Ecosystem but also immigration by new females. Subadult males primarily emigrated out of the system, but one male remained philopatric. Our results highlighted the notion that solitary cougars are associating, and potentially interacting, on the landscape with regularity and predictability. Further, our results raised critical questions: If cougars are associating more frequently than previously believed, why do they do so and are these interactions typically agonistic?

Many mammals, both potential competitors and preys, have been reported to use the complex burrow system of European badger Meles meles setts as shelter, mainly in northern Europe and during winter, when badgers are lethargic. Nonetheless, until recent times observations of den sharing have been largely restricted to anecdotal information, because of the mainly nocturnal activity of most sett occupants. Using camera-trapping, we investigated both the mammal fauna associated with 24 badger setts located in northern and central Italy, and seasonal variation in the composition of specific assemblages, without interfering with the occupants’ activity. Trapping effort was 1,605 camera trap-days from December 2010 to December 2013. Badgers (two to six individuals per sett) shared their setts with a total of eight mammal species: crested porcupine Hystrix cristata, Eastern cottontail Sylvilagus floridanus, red fox Vulpes vulpes, pine marten Martes martes, stone marten Martes foina, wood mouse Apodemus sp., brown rat Rattus norvegicus and coypu Myocastor coypus. Den sharing was observed throughout the year, with a significant reduction of sharing during winter, when badgers were probably induced to move to alternative setts to avoid breeding porcupines. Eastern cottontails used badger burrows permanently and, at least in one occasion, reared their pups inside, although they can be easily preyed upon by badgers. Badger sett sharing may have favoured both the recent northward expansion of crested porcupines and settling of introduced cottontails in agricultural habitats.