Comparative Study on the Social Behavior of Sambar Deer (Rusa Unicolor) in Three Selected Captive Facilities in Peninsular Malaysia

Sambar deer was up-listed from Least Concern to Vulnerable by the IUCN Red list in 2015. The local government has initiated Ex-situ conservation efforts to boost sambar deer numbers in captivity and reintroduce them into the wild. The reproductive success of sambar deer and their welfare management practices in captivity are important components for effective captive breeding programs. However, there has been a lack of study on sambar deer in recent years, especially about their behavior in captivity. This study aimed to identify environmental factors that may influence the behavior of the captive sambar. Three captive sites were selected and observed for an average of 40 days at each site (minimum 37 days to maximum 43 days, 6 hours/day). A Generalized Linear Model was used to determine the correlation between social behavior and extrinsic parameters. ‘Captive sites’ showed the strongest correlation in behavioral variability environmental settings, such as the size of the enclosure, could force the deer to spend more time in a herd, which increases the frequency in grooming, which was recorded to be highest in Zoo Negara compared to other captive sites. Time of day also significantly influenced certain behavior skewed towards morning slots. It could be due to an adaptive behavior to the feeding time in the captive sites being often in the morning, which caused the deer to rest towards the afternoon. A suggestion would be to create a more erratic feeding schedule to ensure that the deer adapt to behavior variations. An extensive study needs to be done on sambar deer to pinpoint the specifics and better understand these possible influential factors in their behavior.

Filling Gaps in the Nomological Networks for Dominance and Affiliation by Examining Self-Informant Agreement on Momentary Interpersonal Behavior

Interpersonal functioning involves an interplay of subjective perceptions and overt behavior. This study examines agreement between self and informant reports of behavior measured naturalistically to investigate the associations between observable behavior, self-perceptions, and others’ perceptions and to enrich the nomological networks for the domains of dominance and affiliation. We studied a sample of romantic couples (N=193) who rated their own and their partner’s interpersonal behavior during a 21-day ambulatory assessment (AA) protocol. We used a multitrait-multimethod-multirater correlation matrix including self- and informant-reported averages and variability of dominance and affiliation measured by AA and cross-sectional self-reports of dominance, affiliation, and interpersonal distress. There was no self-informant agreement on dominance measured by AA, but there was moderate agreement on affiliation averages and variability. Only AA self-reports of average dominance and affiliation, not informant reports, converged with analogous cross-sectional self-reports. Both self and informant reports of dominance and affiliation variability correlated with self-reported interpersonal distress. Results suggest that the internal versus external experiences of dominance and affiliation differ and that these differences have important implications in everyday interpersonal functioning. Our findings also show that self-perceptions of variability in dominance and affiliation, others’ perceptions of variability, and actual behavioral variability relate to interpersonal problems.

Failure to account for behavioral variability overestimates bonobo populations and compromises accuracy in population monitoring

Wildlife population monitoring depends on accurate counts of individual animals or artefacts of behavior (e.g., nests or dung), but also must account for potential biases in the likelihood to encounter these animals or artefacts. In indirect surveying, which depends largely upon artefacts of behavior, likelihood to encounter indirect signs of a species is derived from both artefact production and decay. Although environmental context as well as behavior contribute to artefact abundance, variability in behaviors relevant to artefact abundance is rarely considered in population estimation. Here we demonstrate how ignoring behavioral variability contributes to overestimation of population size of a highly endangered great ape endemic only to the Democratic Republic of the Congo, the bonobo (Pan paniscus). Variability in decay of signs of bonobo presence (i.e., nests) is well documented and linked to environmental determinants. Conversely, a single metric of sign production (i.e., nest construction) is commonly used to estimate bonobo density, assumed to be representative of bonobo nest behavior across all contexts. We estimated nest construction rates from three bonobo groups within the Kokolopori Bonobo Reserve and found that nest construction rates in bonobos to be highly variable across populations as well as seasonal within populations. Failure to account for behavioral variability in nest construction leads to potentially severe degradation in accuracy of bonobo population estimates of abundance, accounting for a likely overestimation of bonobo numbers by 34%, and in the worst cases as high as 80% overestimation. Using bonobo nesting as an example, we demonstrate that failure to account for inter- and intra-population behavioral variation compromises our ability to monitor population change or reliably compare contributors to population decline or persistence. We argue that variation in sign production is but one of several potential ways that behavioral variability can affect conservation monitoring, should be measured across contexts whenever possible, and must be considered in population estimation confidence intervals. With increasing attention to behavioral variability as a potential tool for conservation, conservationists must also account for the impact that behavioral variability across time, space, individuals, and populations can play upon precision and accuracy of wildlife population estimation.

Precise quantification of behavioral individuality from 80 million decisions across 183,000 flies

Individual animals behave differently from each other. This variability is a component of personality and arises even when genetics and environment are held constant. Discovering the biological mechanisms underlying behavioral variability depends on efficiently measuring individual behavioral bias, a requirement that is facilitated by automated, high-throughput experiments. We compiled a large data set of individual locomotor behavior measures, acquired from over 183,000 fruit flies walking in Y-shaped mazes. With this data set we first conducted a "computational ethology natural history" study to quantify the distribution of individual behavioral biases with unprecedented precision and examine correlations between behavioral measures with high power. We discovered a slight, but highly significant, left-bias in spontaneous locomotor decision-making. We then used the data to evaluate standing hypotheses about biological mechanisms affecting behavioral variability, specifically: the neuromodulator serotonin and its precursor transporter, heterogametic sex, and temperature. We found a variety of significant effects associated with each of these mechanisms that were behavior-dependent. This indicates that the relationship between biological mechanisms and behavioral variability may be highly context dependent. Going forward, automation of behavioral experiments will likely be essential in teasing out the complex causality of individuality.

Matching physical properties of food and tools in three populations of wild capuchin monkeys

Robust capuchin monkeys (Sapajus) are known for accessing mechanically challenging food. Although presenting morphological adaptations to do so, several populations go beyond the body limitations, using tools, mainly stone tools, to expand their food range. Those populations are diverse, some using stones more widely than others. We know stone tool size correlates with the target's resistance within some populations, but we have no detailed comparisons between populations so far. This study described and compared general environmental data, food’s physical properties, and stone tools features on three populations of bearded capuchin monkeys (Sapajus libidinosus), including a new site. The differences we observed regarding stone tool use between the new site (CVNP) and the previously studied ones could be partially explained by ecological factors, such as the raw material and resource availability. However, other differences appear to be more related to behavioral traditions, such as the processing of Hymenaea at CVNP, where the monkeys use bigger stones than other populations to process the same kind of food, which present similar physical properties between sites. Possible cultural differences need to be compared within a larger number of areas to better understand capuchin monkey behavioral variability.

Salience of multisensory feedback regulates behavioral variability

Many animal behaviors are robust to dramatic variations in morphophysiological features, both across and within individuals. The control strategies that animals use to achieve such robust behavioral performances are not known. Recent evidence suggests that animals rely on sensory feedback rather than precise tuning of neural controllers for robust control. Here we examine the structure of sensory feedback, including multisensory feedback, for robust control of animal behavior. We re-examined two recent datasets of refuge tracking responses of Eigenmannia virescens, a species of weakly electric fish. Eigenmannia rely on both the visual and electrosensory cues to track the position of a moving refuge. The datasets include experiments that varied the strength of visual and electrosensory signals. Our analyses show that increasing the salience (perceptibility) of visual or electrosensory signals resulted in more robust and precise behavioral responses. Further, we find that robust performance was enhanced by multisensory integration of simultaneous visual and electrosensory cues. These findings suggest that engineers may achieve better system performance by improving the salience of multisensory feedback rather than solely focusing on precisely tuned controllers.

Behavioral and molecular underpinnings of performance variability in eyeblink conditioning in male and female mice

The functional and molecular sources of behavioral variability in mice are not fully understood. As a consequence, the predominant use of male mice has become a standard in animal reseach, under the assumption that males are less variable than females. Similarly, to homogenize genetic background, neuroscience studies have almost exclusively used the C57BL/6 (B6) strain. Here, we examined individual differences in performance in the context of associative learning. We performed delayed eyeblink conditioning while recording locomotor activity in mice from both sexes in two strains (B6 and B6CBAF1). Further, we used a C-FOS immunostaining approach to explore brain areas involved in eyeblink conditioning across subjects, and correlate them with behavioral performance. We found that B6 male and female mice show comparable variability in this task and that females reach higher learning scores. We found a strong positive correlation across sexes between learning scores and voluntary locomotion. C-FOS immunostainings revealed positive correlations between C-FOS positive cell density and learning in the cerebellar cortex as well as multiple, previously unreported extra-cerebellar areas. We found consistent and comparable correlations in eyeblink performance and C-fos expression in B6 and B6CBAF1 females and males. Taken together, we show that differences in motor behavior and activity across brain areas correlate with learning scores during eyeblink conditioning across strains and sexes.

Thermal modulation of Zebrafish exploratory statistics reveals constraints on individual behavioral variability

Background Variability is a hallmark of animal behavior. It contributes to survival by endowing individuals and populations with the capacity to adapt to ever-changing environmental conditions. Intra-individual variability is thought to reflect both endogenous and exogenous modulations of the neural dynamics of the central nervous system. However, how variability is internally regulated and modulated by external cues remains elusive. Here, we address this question by analyzing the statistics of spontaneous exploration of freely swimming zebrafish larvae and by probing how these locomotor patterns are impacted when changing the water temperatures within an ethologically relevant range. Results We show that, for this simple animal model, five short-term kinematic parameters — interbout interval, turn amplitude, travelled distance, turn probability, and orientational flipping rate — together control the long-term exploratory dynamics. We establish that the bath temperature consistently impacts the means of these parameters, but leave their pairwise covariance unchanged. These results indicate that the temperature merely controls the sampling statistics within a well-defined kinematic space delineated by this robust statistical structure. At a given temperature, individual animals explore the behavioral space over a timescale of tens of minutes, suggestive of a slow internal state modulation that could be externally biased through the bath temperature. By combining these various observations into a minimal stochastic model of navigation, we show that this thermal modulation of locomotor kinematics results in a thermophobic behavior, complementing direct gradient-sensing mechanisms. Conclusions This study establishes the existence of a well-defined locomotor space accessible to zebrafish larvae during spontaneous exploration, and quantifies self-generated modulation of locomotor patterns. Intra-individual variability reflects a slow diffusive-like probing of this space by the animal. The bath temperature in turn restricts the sampling statistics to sub-regions, endowing the animal with basic thermophobicity. This study suggests that in zebrafish, as well as in other ectothermic animals, ambient temperature could be used to efficiently manipulate internal states in a simple and ethological way.

Coupling between motor cortex and striatum increases during sleep over long-term skill learning

The strength of cortical connectivity to the striatum influences the balance between behavioral variability and stability. Learning to consistently produce a skilled action requires plasticity in corticostriatal connectivity associated with repeated training of the action. However, it remains unknown whether such corticostriatal plasticity occurs during training itself or 'offline' during time away from training, such as sleep. Here, we monitor the corticostriatal network throughout long-term skill learning in rats and find that non-REM (NREM) sleep is a relevant period for corticostriatal plasticity. We first show that the offline activation of striatal NMDA receptors is required for skill learning. We then show that corticostriatal functional connectivity increases offline, coupled to emerging consistent skilled movements and coupled cross-area neural dynamics. We then identify NREM sleep spindles as uniquely poised to mediate corticostriatal plasticity, through interactions with slow oscillations. Our results provide evidence that sleep shapes cross-area coupling required for skill learning.