Some animal species have been presumed to be purely diurnal. Yet, they show flexibility in their activity rhythm, and can occasionally be active at night. Recently, it has been suggested that ...chimpanzees may rarely engage in nocturnal activities in savannah forests, in contrast to the frequent nocturnal feeding of crops observed at Sebitoli, Kibale National Park, Uganda. Here we thus aimed to explore the factors that might trigger such intense nocturnal activity (e.g. harsher weather conditions during daytime, low wild food availability or higher diurnal foraging risk) in this area. We used camera-traps set over 18 km2 operating for 15 months. We report activities and group composition from records obtained either within the forest or at the forest interface with maize fields, the unique crop consumed. Maize is an attractive and accessible food source, although actively guarded by farmers, particularly during daytime. Out of the 19 156 clips collected, 1808 recorded chimpanzees. Of these, night recordings accounted for 3.3% of forest location clips, compared to 41.8% in the maize fields. Most nocturnal clips were obtained after hot days, and most often during maize season for field clips. At night within the forest, chimpanzees were travelling around twilight hours, while when at the border of the fields they were foraging on crops mostly after twilight and in smaller parties. These results suggest that chimpanzees change their activity rhythm to access cultivated resources when human presence and surveillance is lower. This survey provides evidence of behavioral plasticity in chimpanzees in response to neighboring human farming activities, and emphasizes the urgent need to work with local communities to mitigate human-wildlife conflict related to crop-feeding.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Cognitive abilities enabling animals that feed on ephemeral but yearly renewable resources to infer
resources are available may have been favoured by natural selection, but the magnitude of the ...benefits brought by these abilities remains poorly known. Using computer simulations, we compared the efficiencies of three main types of foragers with different abilities to process temporal information, in spatially and/or temporally homogeneous or heterogeneous environments. One was endowed with a
memory, which stores recent experience about the availability of the different food types. The other two were endowed with a
or
memory, which stores long-term temporal information about absolute times of these availabilities or delays between them, respectively. To determine the range of possible efficiencies, we also simulated a forager without temporal cognition but which simply targeted the closest and possibly empty food sources, and a perfectly prescient forager, able to know at any time which food source was effectively providing food. The
,
and
foragers were far more efficient than the forager without temporal cognition in temporally predictable environments, and interestingly, their efficiencies increased with the level of temporal heterogeneity. The use of a long-term temporal memory results in a foraging efficiency up to 1.16 times better (
memory) or 1.14 times worse (
memory) than the use of a simple
memory. Our results thus show that, for everyday foraging, a long-term temporal memory did not provide a clear benefit over a simple short-term memory that keeps track of the current resource availability. Long-term temporal memories may therefore have emerged in contexts where short-term temporal cognition is useless, i.e. when the anticipation of future environmental changes is strongly needed.
Within comparative psychology, the evolution of animal cognition is typically studied either by comparing indirect measures of cognitive abilities (e.g., relative brain size) across many species or ...by conducting batteries of decision-making experiments among (typically) a few captive species. Here, we propose a third, complementary approach: inferring and comparing cognitive abilities through observational field records of natural information gradients and the associated variation in decision-making outcomes, using the ranging behavior of wild animals. To demonstrate the feasibility of our proposal, we present the results of a global survey assessing the availability of long-term ranging data sets from wild primates and the willingness of primatologists to share such data. We explore three ways in which such ranging data, with or without the associated behavioral and ecological data often collected by primatologists, might be used to infer and compare spatial cognition. Finally, we suggest how ecological complexity may be best incorporated into comparative analyses.
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•Comparing animal ranging decisions in natural habitats has untapped potential•How decisions vary with natural information gradients reveals wild animal cognition•Ranging data on at least 164 populations of 105 wild primate species are available•We present three thought analyses to compare cognition and explain its evolution
Biological Sciences; Neuroscience; Cognitive Neuroscience
Foraging in seasonal environments can be cognitively challenging. Comparative studies have associated brain size with a frugivorous diet. We investigated how fruit distribution (
) and preference (
) ...affect foraging decisions in three semi-free ranging primate species with different degrees of frugivory:
(
= 5;
= 430),
(
= 3;
= 168) and
(
= 6;
= 288). We used 36 boxes fixed on trees and filled with highly and less preferred fruits with different (weekly) spatio-temporal distributions. Individuals were tested in two conditions: (1) same fruit provided concurrently in the same quantity but in a scattered and in a clumped distribution, (2) highly preferred fruit was scattered while the less preferred was clumped. Generally, primates preferred feeding first on the boxes of the clumped distribution in both conditions, with the more frugivorous species at a higher degree than the less frugivorous species in condition (1), but not (2). Therefore,
fruit was available changed the foraging decisions of the more frugivorous species who also engaged more in goal-directed travel. When feeding on preferred fruit, primates probably maximized foraging efficiency regardless of their degree of frugivory. Our findings emphasize that the food type and distribution may be a preponderant driver in cognitive evolution.
Abstract
The increase of wind turbine installations to limit climate change may affect bird populations because of collisions with rotor blades. Birds may respond to wind turbine presence along a ...gradient of behavioral changes: avoiding the wind farm (macro-scale) or the wind turbines either by anticipating wind turbine locations (meso-scale) or engaging in last-minute flee attempts (micro-scale). We investigated flight responses of 25 adult Gyps fulvus (Griffon Vulture) equipped with GPS tags over 3 yr in an area that included 10 wind farms in Causses, France. At the macro-scale, foraging range and habitat use revealed that G. fulvus did not avoid wind farms. To investigate avoidance at meso- and micro-scales, we focused on the 4 most visited wind farms. We compared vulture flights to null movement models, which allowed us to keep the correlation between flights and topography while creating movement independent of wind turbine locations. At most sites, G. fulvus did not show avoidance behavior. Overall, our results suggest wind farm-specific responses by soaring birds as a function of landscape topography. Thus, to reduce collision risks, stakeholders should first avoid constructing wind farms close to vulture nesting colonies. When siting, developers should investigate G. fulvus use of local topography to avoid areas in which birds are likely to travel. Finally, managers must prioritize the detection of species not able to avoid turbines when designing preventive measures, such as switching off on-demand technologies.
The main hypotheses on the evolution of animal cognition emphasise the role of conspecifics in affecting the socio-ecological environment shaping cognition. Yet, space is often simultaneously ...occupied by multiple species from the same ecological guild. These sympatric species can compete for food, which may thereby stimulate or hamper cognition. Considering brain size as a proxy for cognition, we tested whether species sympatry impacted the evolution of cognition in frugivorous primates. We first retraced the evolutionary history of sympatry between frugivorous primate lineages. We then fitted phylogenetic models of the evolution of the size of several brain regions in frugivorous primates, considering or not species sympatry. We found that the evolution of the whole brain or brain regions used in immediate information processing was best fitted with models not considering sympatry. By contrast, models considering species sympatry best predicted the evolution of brain regions related to long-term memory of interactions with the socio-ecological environment, with a decrease in their size the higher the sympatry. We speculate that species sympatry, by generating intense food depletion, might lead to an over-complexification of resource spatiotemporality that counteracts the benefits of high cognitive abilities and/or might drive niche partitioning and specialisation, thereby inducing lower brain region sizes. In addition, we reported that primate species in sympatry diversify more slowly. This comparative study suggests that species sympatry significantly contributes to shaping primate evolution.
The use of social information in vulture flight decisions Sassi, Yohan; Nouzières, Basile; Scacco, Martina ...
Proceedings - Royal Society. Biological sciences/Proceedings - Royal Society. Biological Sciences,
2024-Mar-13, 2024-03-13, 20240313, Letnik:
291, Številka:
2018
Journal Article
Recenzirano
Odprti dostop
Animals rely on a balance of personal and social information to decide when and where to move next in order to access a desired resource. The benefits from cueing on conspecifics to reduce ...uncertainty about resource availability can be rapidly overcome by the risks of within-group competition, often exacerbated toward low-ranked individuals. Being obligate soarers, relying on thermal updraughts to search for carcasses around which competition can be fierce, vultures represent ideal models to investigate the balance between personal and social information during foraging movements. Linking dominance hierarchy, social affinities and meteorological conditions to movement decisions of eight captive vultures,
., released for free flights in natural soaring conditions, we found that they relied on social information (i.e. other vultures using/having used the thermals) to find the next thermal updraught, especially in unfavourable flight conditions. Low-ranked individuals were more likely to disregard social cues when deciding where to go next, possibly to minimize the competitive risk of social aggregation. These results exemplify the architecture of decision-making during flight in social birds. It suggests that the environmental context, the context of risk and the social system as a whole calibrate the balance between personal and social information use.
Animal foraging movements are shaped by sensory-motor abilities, availability and distribution of resources and cognitive skills (memory of where, and possibly what and when, food is available). ...Inferring a movement process (i.e. the decision rules controlling where to go at any time) from a given movement pattern (i.e. the distributions of some key variables such as the step length or the turning angle) is usually tricky because the same process can generate different patterns depending on the context while similar patterns can be generated by different processes. However, animal movement studies combining statistical (pattern-based) and mechanistic (process-based) approaches can provide valuable insights into the knowledge an animal has of its environment. This knowledge can range between the two extreme cases of a fully naïve animal finding food only by chance and an omniscient animal knowing where, when, what and how much food is available at any time. Based on 2 years of 20min scan sampling of ranging and feeding behaviour, we investigated the foraging movements of two habituated groups of wild western gorillas, Gorilla gorilla, a seasonally frugivorous primate species inhabiting Central African lowland forests. We showed that gorillas may choose the next feeding site by following a movement heuristic favouring the nearest-neighbour feeding site of the highest long-term interest (inferred a posteriori as the total time spent within it over a whole season) likely to yield food at this time. Thus, gorillas seemed to rely on an accurate spatial memory, enabling them to know where the places liable to yield food are located but have limited knowledge of how much food they can find at a given place at a given time. Our study shows how integrative statistical analysis and mechanistic modelling may help improve our understanding of movements and cognition in numerous species.
•Animal movement heuristics should vary depending on the level of cognition involved.•Gorilla movements between feeding sites do not correspond to a Lévy walk.•Gorillas plan their foraging movements using spatiotemporal memory.•Cognitive foraging by gorillas occurs during both the high- and low-frugivory seasons.•Animal movements can be deciphered by mixing mechanistic and statistical modelling.
The relative importance of individual and social learning in acquiring complex technological skills in animals is debated, especially the influence of processes allowing high copying fidelity ...(namely, imitation and teaching). We investigated how immature wild chimpanzees, Pan troglodytes troglodytes, acquired the technique for extracting underground honey. This technique is interesting because (1) adults perform exploration, pounding and perforation in nonrandom but highly flexible action sequences to locate underground bee nests, (2) they have individual preferences for how to perforate the ground and (3) the nests are deeply buried and concealed, making success difficult to achieve. We analysed the behaviour of 16 immatures recorded by camera traps at 50 sites, and tested the influence of individual attributes (namely, age and sex) and maternal behaviour; we also tested whether mothers provided learning opportunities for their offspring. We found that, as they aged, immatures of both sexes progressively matched adults' behaviour in action sequences and observed their social models more continuously. Immature males used the most common grip type used by adults for perforating (namely, the coordinated use of hands and feet) progressively more as they aged, but no effect of maternal preferences was detected. Thus, the adult technique was probably acquired via a combination of physical maturation (i.e. increased body strength and motor coordination) and observational learning, although individual learning could not be completely ruled out. Finally, the proportion of time mothers spent inactive at bee nest sites was high when they were accompanied by young daughters and decreased as daughters aged, while the opposite pattern was found for sons. Mothers may thus stimulate learning by immatures by adjusting their behaviour according to their offspring's sex and age. Overall, we showed that immature chimpanzees acquired this complex tool use behaviour via a combination of social and nonsocial learning processes, including potential maternal stimulation.
•Immature chimpanzees acquired action sequences for honey extraction as they aged.•With age, immatures used the grip type involving hands and feet more to perforate.•One immature male learned the grip type unique to his mother.•Mothers provided learning opportunities to offspring according to their age and sex.
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