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- Basal cognition: shifting the center of gravity (again)
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PubDate: 2023-11-06
- Hoarding titmice predominantly use Familiarity, and not Recollection, when
remembering cache locations-
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Abstract: Abstract Scatter-hoarding birds find their caches using spatial memory and have an enlarged hippocampus. Finding a cache site could be achieved using either Recollection (a discrete recalling of previously experienced information) or Familiarity (a feeling of “having encountered something before”). In humans, these two processes can be distinguished using receiver operating characteristic (ROC) curves. ROC curves for olfactory memory in rats have shown the hippocampus is involved in Recollection, but not Familiarity. We test the hypothesis that food-hoarding birds, having a larger hippocampus, primarily use Recollection to find their caches. We validate a novel method of constructing ROC curves in humans and apply this method to cache retrieval by coal tits (Periparus ater). Both humans and birds mainly use Familiarity in finding their caches, with lower contribution of Recollection. This contribution is not significantly different from chance in birds, but a small contribution cannot be ruled out. Memory performance decreases with increasing retention interval in birds. The ecology of food-hoarding Parids makes it plausible that they mainly use Familiarity in the memory for caches. The larger hippocampus could be related to associating cache contents and temporal context with cache locations, rather than Recollection of the spatial information itself.
PubDate: 2023-10-21
- Spot the odd one out: do snake pictures capture macaquesā attention more
than other predators'-
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Abstract: Abstract Detecting and identifying predators quickly is key to survival. According to the Snake Detection Theory (SDT), snakes have been a substantive threat to primates for millions of years, so that dedicated visual skills were tuned to detect snakes in early primates. Past experiments confronted the SDT by measuring how fast primate subjects detected snake pictures among non-dangerous distractors (e.g., flowers), but did not include pictures of primates’ other predators, such as carnivorans, raptors, and crocodilians. Here, we examined the detection abilities of N = 19 Tonkean macaques (Macaca tonkeana) and N = 6 rhesus macaques (Macaca mulatta) to spot different predators. By implementing an oddity task protocol, we recorded success rates and reaction times to locate a deviant picture among four pictures over more than 400,000 test trials. Pictures depicted a predator, a non-predator animal, or a simple geometric shape. The first task consisted of detecting a deviant picture among identical distractor pictures (discrimination) and the second task was designed to evaluate detection abilities of a deviant picture among different distractor pictures (categorization). The macaques detected pictures of geometric shapes better and faster than pictures of animals, and were better and faster at discriminating than categorizing. The macaques did not detect snakes better or faster than other animal categories. Overall, these results suggest that pictures of snakes do not capture visual attention more than other predators, questioning previous findings in favor of the SDT.
PubDate: 2023-10-19
- Cognitive flexibility in a Tanganyikan bower-building cichlid,
Aulonocranus dewindti-
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Abstract: Abstract Cognitive flexibility, the ability to modify one’s decision rules to adapt to a new situation, has been extensively studied in many species. In fish, though, data on cognitive flexibility are scarce, especially in the wild. We studied a lekking species of cichlid fish in Lake Tanganyika, Aulonocranus dewindti. Males create sand bowers as spawning sites and maintain them by removing any objects falling into it. In the first part of our experiment, we investigated the existence of spontaneous decision rules for the maintenance of the bowers. We showed that if a snail shell and a stone are placed in their bower, fish prefer to remove the shell first. In the second phase of our experiment, we took advantage of this spontaneous decision rule to investigate whether this rule was flexible. We tested five individuals in a choice against preference task, in which the fish had to modify their preference rule and remove the stone first to be allowed to then remove the shell and have a clean bower. While there was no overall trend towards flexibility in this task, there was variation at an individual level. Some individuals increased their preference for removing the shell first, deciding quickly and with little exploration of the objects. Others were more successful at choosing against preference and showed behaviours suggesting self-regulatory inhibition abilities. Bower-building cichlids could therefore be a promising model to study cognitive flexibility, and other aspects of animal cognition in the wild.
PubDate: 2023-10-18
- Interspecific differences in developmental mode determine early cognitive
abilities in teleost fish-
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Abstract: Abstract Most studies on developmental variation in cognition have suggested that individuals are born with reduced or absent cognitive abilities, and thereafter, cognitive performance increases with age during early development. However, these studies have been mainly performed in altricial species, such as humans, in which offspring are extremely immature at birth. In this work, we tested the hypothesis that species with other developmental modes might show different patterns of cognitive development. To this end, we analysed inhibitory control performance in two teleost species with different developmental modes, the zebrafish Danio rerio and the guppy Poecilia reticulata, exploiting a simple paradigm based on spontaneous behaviour and therefore applicable to subjects of different ages. Zebrafish hatch as larvae 3 days after fertilisation, and have an immature nervous system, a situation that mirrors extreme altriciality. We found that at the early stages of development, zebrafish displayed no evidence of inhibitory control, which only begun to emerge after one month of life. Conversely, guppies, which are born after approximately one month of gestation as fully developed and independent individuals, solved the inhibitory control task since their first days of life, although performance increased with sexual maturation. Our study suggests that the typical progression described during early ontogeny in humans and other species might not be the only developmental trend for animals’ cognition and that a species’ developmental mode might determine variation in cognition across subjects of different age.
PubDate: 2023-10-13
- Use of the sun compass by monocularly occluded homing pigeons in a food
localisation task in an outdoor arena-
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Abstract: Abstract Functional asymmetries of the avian visual system can be studied in monocularly occluded birds, as their hemispheres are largely independent. Right and left monocularly occluded homing pigeons and control birds under binocular view have been trained in a food localisation task in an octagonal outdoor arena provided with one coloured beacon on each wall. The three groups were tested after the removal of the visual beacons, so to assess their sun compass learning abilities. Pigeons using the left eye/right hemisphere system exhibited slower learning compared to the other monocular group. During the test in the arena void of visual beacons, the three groups of birds, regardless of their visual condition, were generally able to identify the training sector by exclusively relying on sun compass information. However, the directional choices of the pigeons with the left eye/right hemisphere in use were significantly affected by the removal of the beacons, while both control pigeons and birds with the right eye/left hemisphere in use displayed unaltered performances during the test. A subsample of pigeons of each group were re-trained in the octagonal arena with visual beacons present and tested after the removal of visual beacons after a 6 h fast clock-shift treatment. All birds displayed the expected deflection consistent to the sun compass use. While birds using either the left or the right visual systems were equally able to learn a sun compass-mediated spatial task, the left eye/right hemisphere visual system displayed an advantage in relying on visual beacons.
PubDate: 2023-10-10
- “The song remains the same”: not really! Vocal flexibility in
the song of the indris-
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Abstract: Abstract In studying communicative signals, we can think of flexibility as a necessary correlate of creativity. Flexibility enables animals to find practical solutions and appropriate behaviors in mutable situations. In this study, we aimed to quantify the degree of flexibility in the songs of indris (Indri indri), the only singing lemur, using three different metrics: Jaro Distance, normalized diversity, and entropy. We hypothesized that the degree and the co-variation of the flexibility of indris singing together would vary according to their status and sex. We found that dominant females were more flexible than dominant males when concatenating elements into strings (element concatenation). The number of different elements in a song contribution normalized by the contribution length (contribution diversity) of dominant individuals positively co-varied for seven duetting pairs. Non-dominant individuals were more variable in element concatenation than dominant individuals, and they were more diverse in phrase type than dominant females. Independently from sex and status, individual contributions did not differ in entropy (a measure of the predictability of contributions). These results corroborate previous findings regarding the dimorphism by sex and by status of individual contributions to songs. Thus, they shed light on the presence and expression of flexibility in the behavior of a non-human primate species. Indeed, they potentially show an effect of social features in shaping vocal flexibility, which underlies many communication systems, including human language. We speculate that this degree of flexibility may account for creativity.
PubDate: 2023-10-04
- Orientation by environmental geometry and feature cues in the green and
black poison frog (Dendrobates auratus)-
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Abstract: Abstract The ability to use environmental geometry when orienting in space reflects an animal’s ability to use a global, allocentric framework. Therefore, understanding when and how animal’s use geometry relative to other types of cues in the environment has interested comparative cognition researchers for decades. Yet, only two amphibians have been tested to date. We trained the poison frog Dendrobates auratus to find goal shelters in a rectangular arena, in the presence and absence of a feature cue, and assessed the relative influence of the two types of cues using probe trials. We chose D. auratus because the species has complex interactions with their physical and social environments, including parental care that requires navigating to and from distant locations. We found that, like many vertebrates, D. auratus are capable of using geometric information to relocate goals. In addition, the frogs preferentially used the more reliable feature cue when the location of the feature conflicted with the geometry of the arena. The frogs were equally successful at using the feature cue when it was proximal or distal to the goal shelter, consistent with prior studies that found that D. auratus can use distal cues in a flexible manner. Our results provide further evidence that amphibians can use environmental geometry during orientation. Future studies that examine when and how amphibians use geometry relative to other types of cues will contribute to a more complete picture of spatial cognition in this important, yet understudied, group.
PubDate: 2023-09-12
- First acoustic evidence of signature whistle production by spinner
dolphins (Stenella longirostris)-
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Abstract: Abstract A dolphin’s signature whistle (SW) is a distinctive acoustic signal, issued in a bout pattern of unique frequency modulation contours; it allows individuals belonging to a given group to recognize each other and, consequently, to maintain contact and cohesion. The current study is the first scientific evidence that spinner dolphins (Stenella longirostris) produce SWs. Acoustic data were recorded at a shallow rest bay called “Biboca”, in Fernando de Noronha Archipelago, Brazil. In total, 1902 whistles were analyzed; 40% (753/1,902) of them were classified as stereotyped whistles (STW). Based on the SIGID method, 63% (472/753) of all STWs were identified as SWs; subsequently, they were categorized into one of 18 SW types. SWs accounted for 25% (472/1,902) of the acoustic repertoire. External observers have shown near perfect agreement to classify whistles into the adopted SW categorization. Most acoustic and temporal variables measured for SWs showed mean values similar to those recorded in other studies with spinner dolphins, whose authors did not differentiate SWs from non-SWs. Principal component analysis has explained 78% of total SW variance, and it emphasized the relevance of shape/contour and frequency variables to SW variance. This scientific discovery helps improving bioacoustics knowledge about the investigated species. Future studies to be conducted in Fernando de Noronha Archipelago should focus on continuous investigations about SW development and use by S. longirostris, expanding individuals’ identifications (Photo ID and SW Noronha Catalog), assessing long-term whistle stability and emission rates, and making mother–offspring comparisons with sex-based differences.
PubDate: 2023-09-07
- Grouping rule in tadpole: is quantity more or size assortment more
important'-
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Abstract: Abstract The ability to perceive group size and discriminate the ontogeny of conspecifics would play a crucial role in the grouping behavior of animals. However, the relative importance of numerical quantity and size-assortative preferences in shaping grouping rules remains poorly understood. In this study, I examined the responses of Miyako toad (Bufo gargarizans miyakonis) tadpoles to number quantity and size discrimination by choice tests at different ontogenetic stages (small, medium, and large). The results revealed that small-sized tadpoles in early developmental stages significantly preferred larger numbers (4) compared to smaller ones (1). However, this preference was not observed in later developmental stages (medium and large). And interestingly, when there was no quantity bias, size discrimination was not observed in tadpoles, irrespective of their ontogeny. These findings suggest that Miyako toad tadpoles discern quantity, i.e., the number of conspecifics, but exhibit ontogeny-dependent utilization of this ability. Understanding the interplay between numerical quantity and size-assortative preferences in grouping behavior will provide esteemed insights into the adaptive value of number sense in vertebrates and shed light on evolutionary processes.
PubDate: 2023-09-05
DOI: 10.1007/s10071-023-01823-9
- Active oscillations in microscale navigation
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Abstract: Abstract Living organisms routinely navigate their surroundings in search of better conditions, more food, or to avoid predators. Typically, animals do so by integrating sensory cues from the environment with their locomotor apparatuses. For single cells or small organisms that possess motility, fundamental physical constraints imposed by their small size have led to alternative navigation strategies that are specific to the microscopic world. Intriguingly, underlying these myriad exploratory behaviours or sensory functions is the onset of periodic activity at multiple scales, such as the undulations of cilia and flagella, the vibrations of hair cells, or the oscillatory shape modes of migrating neutrophils. Here, I explore oscillatory dynamics in basal microeukaryotes and hypothesize that these active oscillations play a critical role in enhancing the fidelity of adaptive sensorimotor integration.
PubDate: 2023-09-04
DOI: 10.1007/s10071-023-01819-5
- What do zebra finches learn besides singing' Systematic mapping of the
literature and presentation of an efficient associative learning test-
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Abstract: Abstract The process of learning in birds has been extensively studied, with a focus on species such as pigeons, parrots, chickens, and crows. In recent years, the zebra finch has emerged as a model species in avian cognition, particularly in song learning. However, other cognitive domains such as spatial memory and associative learning could also be critical to fitness and survival, particularly during the intensive juvenile period. In this systematic review, we provide an overview of cognitive studies on zebra finches, with a focus on domains other than song learning. Our findings indicate that spatial, associative, and social learning are the most frequently studied domains, while motoric learning and inhibitory control have been examined less frequently over 30 years of research. All of the 60 studies included in this review were conducted on captive birds, limiting the generalizability of the findings to wild populations. Moreover, only two of the studies were conducted on juveniles, highlighting the need for more research on this critical period of learning. To address this research gap, we propose a high-throughput method for testing associative learning performance in a large number of both juvenile and adult zebra finches. Our results demonstrate that learning can occur in both age groups, thus encouraging researchers to also perform cognitive tests on juveniles. We also note the heterogeneity of methodologies, protocols, and subject exclusion criteria applied by different researchers, which makes it difficult to compare results across studies. Therefore, we call for better communication among researchers to develop standardised methodologies for studying each cognitive domain at different life stages and also in their natural conditions.
PubDate: 2023-09-01
DOI: 10.1007/s10071-023-01795-w
- Mirror self-recognition in ghost crab (Ocypode quadrata)
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Abstract: Abstract Mirror self-recognition has been examined primarily in vertebrate species, largely through the use of a mirror mark test. Recently, however, there has been growing interest in the notion that all animals likely need some form of self-representation to successfully interact with their environment (Kohda et al. in Plos Biol https://doi.org/10.1371/journal.pbio.3001529, 2022; de Waal in Plos Biol https://doi.org/10.1371/journal.pbio.3000112, 2019). Our knowledge of this trait in invertebrate species is particularly limited, while there are several species potentially well suited for mirror mark tests. To better understand this trait and its distribution, the current research examines mirror self-recognition in ghost crab (Ocypode quadrata) using a visual mirror mark test. In an initial phase, animals were exposed to a flat oriented mirror for an extended period. In a subsequent testing phase, subjects were either (1) marked (green sticker) or sham marked (clear sticker) and exposed to a mirror, (2) marked and placed in a tank without a mirror, or (3) marked and shown video of a marked conspecific. Results showed that marked, relative to sham marked, animals were significantly more likely to remove marks when exposed to mirrors. Findings also suggests this behavior was not driven by the perception of mirror images as conspecifics, or issues related to mark placement. These data are interpreted in support of a rudimentary form of self-awareness in this species. Discussions highlight potential cognitive mechanisms that facilitate this type of self-representation and the need for additional research that informs about more sophisticated forms of self-awareness.
PubDate: 2023-09-01
DOI: 10.1007/s10071-023-01800-2
- Chronic social comparison elicits depression- and anxiety-like behaviors
and alterations in brain-derived neurotrophic factor expression in male
rats-
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Abstract: Abstract Social comparison is a fundamental human characteristic; however, long-term social comparison may induce psychological stress and can lead to depression and anxiety. Recent studies have shown that nonhuman primates compare themselves with others; however, no studies have investigated whether social comparisons exist among rodents. In the present study, we established a rat model of social comparison. This model was subsequently used to examine the effects of the differential environment of a partner on depression- and anxiety-like behaviors in male rats, as well as to assess the changes in serum, medial prefrontal cortex (mPFC), and dorsal hippocampus brain-derived neurotrophic factor (BDNF) levels induced by long-term social comparison. Compared to rats whose partners were exposed to the same environment, rats whose partners were exposed to two combined enriched environmental stimuli for 14 days showed significantly decreased social novelty preference and sucrose consumption. No anxiety-like behaviors were observed. Rats whose partners were exposed to one enriched environment for 31 days showed significantly increased immobility time in the forced swimming test, and significantly decreased time spent in the center area in the open-field test. Further, rats whose partners were exposed to one enriched environment for 31 days showed lower BDNF levels in the mPFC and dorsal hippocampus, but not following partner exposure for 14 days. These results suggest that social comparisons exist in rats and can induce psychosocial stress and other negative affect. This model will not only provide the possibility to reveal the neurobiological basis of the emotional impact of social comparison, but could also be used to confirm the conservative evolutionary characteristics of social comparison as a behavioral attribute.
PubDate: 2023-09-01
DOI: 10.1007/s10071-023-01798-7
- Eggshell spots are an important cue for the egg retrieval behavior in two
tit species-
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Abstract: Abstract It is a common occurrence for incubating female ground- or cavity-nesting birds to accidentally roll their own eggs out of the nest cup. To correctly roll eggs that are not in the nest cup back to the nest, birds must be able to discriminate between their eggs and things around their nests that could be easily confused for their eggs (e.g., egg-shaped stones or other birds’ eggs). Moreover, there may be a strong interaction between egg retrieval and egg rejection behaviors in the context of avian brood parasitism where recognition and rejection of alien eggs is an effective means for hosts to defend against cuckoo parasitism. It has been shown that green-backed tits (Parus monticolus) and Japanese tits (P. minor) in China have strong egg recognition ability and are able to reject nonmimetic eggs in the nest. Eggshell spots play an essential role in the egg rejection behavior of these two tit hosts. This study investigated the egg retrieval behavior of green-backed tits and Japanese tits by adding one experimental egg to the nest corner to explore whether eggshell spots also play a role in the process of egg retrieval. The results revealed significant differences in the retrieval rates of white-rumped munia (Lonchura striata) eggs painted with spots, Japanese tits’ own true eggs, and unpainted, pure white-white-rumped munia eggs. The retrieval rate of white-white-rumped munia eggs was significantly lower than that of spotted white-rumped munia eggs and Japanese tits’ own spotted eggs. For green-backed tits, the retrieval rate of spotted white-rumped munia eggs in the nest corner was significantly higher than that of pure white-white-rumped munia eggs, while the rejection rate of spotted white-rumped munia eggs was significantly lower than that of pure white-white-rumped munia eggs. These findings indicate that eggshell spots play a key role in the egg retrieval of green-backed tits and Japanese tits.
PubDate: 2023-07-27
DOI: 10.1007/s10071-023-01814-w
- Reward history modulates visual attention in an avian model
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Abstract: Abstract Attention can be biased towards previously reward-associated stimuli even when they are task-irrelevant and physically non-salient, although studies of reward-modulated attention have been largely limited to primate (including human and nonhuman) models. Birds have been shown to have the capacity to discriminate reward and spatial cues in a manner similar to primates, but whether reward history involuntarily affects their attention in the same way remains unclear. We adapted a spatial cueing paradigm with differential rewards to investigate how reward modulates the allocation of attention in peafowl (Pavo cristatus). The birds were required to locate and peck a target on a computer screen that was preceded by a high-value or low-value color cue that was uninformative with respect to the location of the upcoming target. All birds exhibited a validity effect (performance enhanced on valid compared to invalid cue), and an interaction effect between value and validity was evident at the group level, being particularly pronounced in the birds with the greatest amount of reward training. The time course of reward learning was conspicuously incremental, phenomenologically slower compared to primates. Our findings suggest a similar influence of reward history on attention across phylogeny despite a significant difference in neuroanatomy.
PubDate: 2023-07-21
DOI: 10.1007/s10071-023-01811-z
- Slowly walking down to the more food: relative quantity discrimination in
African spurred tortoises (Centrochelys sulcata)-
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Abstract: Abstract Quantity discrimination, is thought to be highly adaptive as it allows an organism to select greater amounts of food or larger social groups. In contrast to mammals, the processes underlying this ability are not as well understood in reptiles. This study examined the effects of ratio and number size on relative quantity discrimination in African spurred tortoises (Centrochelys sulcata). To assess these effects, tortoises were presented with trays containing favored food pieces in all possible number combinations between 1 and 7. The tortoises had to approach the tray they perceived as having the larger quantity. If correct, they received one piece of food as reinforcement. The results revealed that relative quantity discrimination was influenced by the ratio between the numbers of pieces, with performance improving as the ratio between the numbers increased. This finding suggests that the approximate number system or analogue magnitude estimation may control their behavior. However, as the number size increased, their performance declined, also suggesting that the approximate number system alone could not explain the present results.
PubDate: 2023-07-21
DOI: 10.1007/s10071-023-01812-y
- Singing more, singing harsher: occurrence of nonlinear phenomena in a
primate’ song-
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Abstract: Abstract Nonlinear phenomena (NLP) in animal vocalizations arise from irregularities in the oscillation of the vocal folds. Various non-mutually exclusive hypotheses have been put forward to explain the occurrence of NLP, from adaptive to physiological ones. Non-human primates often display NLP in their vocalizations, yet the communicative role of these features, if any, is still unclear. We here investigate the occurrence of NLP in the song of a singing primate, the indri (Indri indri), testing for the effect of sex, age, season, and duration of the vocal display on their emission. Our results show that NLP occurrence in indri depends on phonation, i.e., the cumulative duration of all the units emitted by an individual, and that NLP have higher probability to be emitted in the later stages of the song, probably due to the fatigue indris may experience while singing. Furthermore, NLP happen earlier in the vocal display of adult females than in that of the adult males, and this is probably due to the fact that fatigue occurs earlier in the former because of a greater contribution within the song. Our findings suggest, therefore, that indris may be subjected to physiological constraints during the singing process which may impair the production of harmonic sounds. However, indris may still benefit from emitting NLP by strengthening the loudness of their signals for better advertising their presence to the neighboring conspecific groups.
PubDate: 2023-07-17
DOI: 10.1007/s10071-023-01809-7
- Does social motivation mitigate fear caused by a sudden sound in
horses'-
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Abstract: Abstract Living in a herd has multiple advantages for social species and is a primary survival strategy for prey. The presence of conspecifics, identified as a social buffer, may mitigate the individual stress response. Social isolation is, therefore, particularly stressful for horses, which are gregarious animals. However, they are not equally vulnerable to separation from the group. We tested whether more and less socially dependent horses and independent individuals would differ in their responses to novel and sudden sounds occurring in two contexts: non-social and social motivation. Twenty warmblood horses were first exposed to two social tests: to evaluate the level of social dependence (rate of restless behaviour; social isolation) and the quantity and the quality of interactions in which they were involved (stay on a paddock). Two fear audio tests were then performed to compare the responses to sudden sounds while feeding (non-social motivation; control trial) and while moving towards the herd (social motivation; experimental trial). Socially dependent horses showed more pronounced avoidance behaviour and needed much more time to resume feeding during the control trial. Hence, dependent individuals appeared to be more fearful. However, during an experimental trial, horses of both groups tended to ignore the sound or paid only limited attention to the stimulus, continuing to move forward towards their conspecifics. Thus, social motivation may mitigate fear caused by a frightening stimulus and make fearful and dependent horses more prone to face a potentially stressful event. This finding should be taken into account in horse training and management.
PubDate: 2023-07-14
DOI: 10.1007/s10071-023-01805-x
- Social information facilitates learning about novel food sources in adult
flower-visiting bats-
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Abstract: Abstract Incorporating novel food sources into their diet is crucial for animals in changing environments. Although the utilization of novel food sources can be learned individually, learning socially from experienced conspecifics may facilitate this task and enable a transmission of foraging-related innovations across a population. In anthropogenically modified habitats, bats (Mammalia: Chiroptera) frequently adapt their feeding strategy to novel food sources, and corresponding social learning processes have been experimentally demonstrated in frugivorous and animalivorous species. However, comparable experiments are lacking for nectarivorous flower-visiting bats, even though their utilization of novel food sources in anthropogenically altered habitats is often observed and even discussed as the reason why bats are able to live in some areas. In the present study, we investigated whether adult flower-visiting bats may benefit from social information when learning about a novel food source. We conducted a demonstrator–observer dyad with wild Pallas’ long-tongued bats (Glossophaga soricina; Phyllostomidae: Glossophaginae) and hypothesized that naïve individuals would learn to exploit a novel food source faster when accompanied by an experienced demonstrator bat. Our results support this hypothesis and demonstrate flower-visiting bats to be capable of using social information to expand their dietary repertoire.
PubDate: 2023-07-08
DOI: 10.1007/s10071-023-01807-9
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