acta ethologica最新文献

While the use of trees has been widely documented for most of the big cats, this information is scant for the jaguar (Panthera onca). In this study, we investigated the use of trees by jaguars, evaluating different underlying reasons as well as the frequency of tree use based on sex, age, and reproductive status. Data were obtained from 2013 to 2020 through a combination of direct observations during fieldwork and camera trapping focused on this behavior in the Brazilian Pantanal. We documented 252 climbing events (176 direct observations, 76 camera captures). Using only camera trapping data to avoid observers’ influence on jaguar behavior, we fitted generalized linear mixed models (GLMM) with jaguar identity as a random factor to test the effects of age, sex, and presence of conspecifics in the odds of animals climbing trees. We also used a generalized linear model (GLM) to test the effect of adult body weight on jaguar tree climbing probability. Age and presence of conspecifics were the most important drivers of jaguar climbing behavior in the study area, with cubs being more likely to climb trees than adults of either sex (odds ratio = 7.91, p < 0.001), and the presence of conspecifics, irrespective of age and sex, accentuated that behavior (odds ratio = 3.26, p < 0.005). Adult females (especially the lighter ones) and cubs were commonly recorded through direct observation on trees, a similar trend to our GLMM that showed a marginally negative effect of body weight on jaguar tree climbing probability. Only a few adult male jaguars ascended trees, and in all cases, these males were following females in heat. We suggest that trees are vertical extensions inside jaguar home ranges and may be safe refuges for resting and for protecting offspring against potential threats, including the harassment of large adult males.

Abstract

Abstract

Animals whose ecological niches largely overlap within a habitat can get into intra-specific and/or inter-specific competition for some of the limited resources available. We hypothesise that differences in locomotor abilities might be a key component deciding which individual will gain the resource, especially in animals with limited agility, such as turtles. To address this hypothesis, we tested self-righting ability and releasing from a vegetation alike rope in two sympatric populations of turtles: Emys orbicularis and Mauremys rivulata. All individuals managed to complete the tests promptly (≤ 103 s). When overturned on their carapace, E. orbicularis had shorter inspecting time, as well as overturning time, indicating slight advantage in self-righting. On the other hand, both species were equally efficient to release from a rope attached to the front of their plastron. The inter-specific morphological differences indicate that muscular strength might be a good predictor of competitive relations among syntopic turtle species.

Toe-tapping, the quick movement of the middle toes of the hind legs, has been observed in many frogs and toads, and is usually associated with feeding, calling, or courtship behaviors. While plenty of observations of toe-tapping exist for different species, experimental evidence regarding the stimuli triggering this behavior is almost non-existent. Here, we systematically tested the influence of different stimuli on the toe-tapping behavior in the green-and-black poison frog (Dendrobates auratus, Dendrobatidae) from a captive colony in the Zoo Frankfurt. We found that, compared to a control, both big and small prey animals (crickets and fruit flies) elicited much more toe-tapping behavior, and that toe-tapping was positively correlated to feeding events. Playback advertisement calls in contrast did not trigger toe-tapping. We further showed that also juvenile frogs already toe-tap, but less frequently than adults. Our results support the observation-based data that toe-tapping is associated with hunting behaviors. While the auditory part of courtship does not seem to trigger toe-tapping, experimental evidence regarding visual and/or tactile courtship stimuli is still lacking.

The addax antelope (Addax nasomaculatus) is a species under serious threat of extinction, as it is more abundant in captivity than in the wild. However, little is known about its basic biology. The aims of this study were to determine how locomotor, feeding, aggressive, marking, and sexual behavior of male addax allocated in all-male groups vary with season and with female contact (i.e., biostimulation). The study was conducted in captive conditions, in two groups of adult males: one with no-physical contact with females, aside from visual and olfactory interactions (CF group, n = 4), and another group completely isolated from females (IF group, n = 4). The frequency of behaviors was recorded during the daytime, 4 days per season (total time of observation = 256 h). Lying, standing, walking, aggressive, marking, grazing, and ruminating behaviors as well as water and supplement consumptions varied with season (all p < 0.05). The lying, walking, marking, grazing, and ruminating behaviors were more frequently observed for CF than IF males (all p < 0.05). Also, all behaviors, except for marking, varied with the interaction between the group and seasons (all p < 0.05). Sexual behavior was extremely scarce, so it was not possible to analyze how it varied with seasons and the group. The present study suggests that management program and housing conditions, especially in ex situ breeding plans, should consider the influence of the season and the sociosexual context on the behavior of addax males.

The Japanese serow (Capricornis crispus) exhibits spatial behavior adapted to forest habitats with relatively stable food supply and climatic conditions, such as sedentary habits, small home ranges, and little seasonal variation in habitat selection. However, investigations have not previously been conducted in open mountainous habitats with high seasonal variability. Therefore, I examined spatial behavior of the Japanese serow in an open mountainous region of Mt. Fuji, central Japan, based on GPS location data. These mountain-dwelling serows had much larger annual home ranges (female: 316.5 ha, male: 373.1 ha) compared with forest-dwelling populations. Spring and summer home range sizes were the largest, and winter home range size was the smallest, ranging from 20.3%–56.1% of maximum. Limited forage and harsh climatic conditions in winter seemed to drive such energy-minimizing behavioral strategies. Selection of vegetation types and elevation varied seasonally, likely because of changes in forage availability and climate conditions. These spatial behaviors in mountain-dwelling serows resemble those of several related mountain ungulates, implying that these behaviors are adaptations to highly seasonal open mountainous habitats. My findings suggest that the main factors affecting spatial behavior are habitat characteristics, such as climate, forage abundance, and seasonality. These findings provide support for an ecological pattern in ungulate spatial behavior whereby closed habitats promote small and stable home ranges, whereas open habitats promote large and seasonally fluctuating home ranges.

The fight or flight decision (i.e., engage in or evade from an interaction) is one of the most important for animals, occurring in many different ecological contexts and dictating the occurrence of agonistic encounters that could lead to injuries or even death. The southern lapwing Vanellus chilensis is one of the most conspicuous bird species from South America, living in the natural grasslands but frequently found in rural and urban area. The species is known by its typical vocalization and its patterns of aggression and territoriality, considered exaggerated, creating a cultural prejudice towards the species. To better understand the agonistic interaction process in the species, we used general linear models to verify the influence of individual characteristics, environmental characteristics, and opponent features on five different response variables related to the interactions: the time of alert behavior display, probability to attack and evade, total duration of the interaction, and the Behavioral Diversity Index (BDI) of each interaction. Despite the models showing that for each response variables the predictors had different importance and weights, it was possible to note that individual features like age, breeding status, and month impact directly the probability to evade or attack, while the opponent species and distance better explained the other variables related to the interaction. The results also showed that the southern lapwings increase the intensity of responses and sensibility to intruder during the breeding season, displaying a trade-off between self-preservation and the protection of the offspring that is present in other bird species.

Abstract