Interspecific association between two primatespecies in an urban park / Associação interespecífica entre duas espécies de primatas em um parque urbano

As with Amazonian primates, mixed associations between species in the Atlantic Forest are also influenced by ecological factors. However, Atlantic Forest primates may face additional challenges, such as isolation pressures and fragmentation of forest habitats, which may increase the frequency of these arrangements. The main of this work is to report a sympatry with possible interaction between individuals of two species of primates of the Pitheciidae and Callitrichidae families: Callicebus nigrifrons (Spix 1823) and Callithrix aurita (É. Geoffroy Saint-Hilaire 1812) in an urban park in the south of the state of Minas Gerais. Individuals were observed interacting during foraging and displacement. The association of individuals of the two species can be explained by the low quality of the forest fragment, as it can increases the chances of obtaining food resources and configures a dilution strategy against predator attacks.

Assim como ocorre com os primatas amazônicos, as associações mistas entre espécies na Mata Atlântica também são influenciadas por fatores ecológicos. No entanto, os primatas da Mata Atlântica podem enfrentar desafios adicionais, como pressões de isolamento e fragmentação de habitats florestais, que podem aumentar a frequência desses arranjos. O objetivo deste trabalho é apresentar um relato de simpatia com possível interação entre indivíduos de duas espécies de primatas das famílias Pitheciidae e Callitrichidae: Callicebus nigrifrons (Spix 1823) e Callithrix Resumo aurita (É. Geoffroy Saint-Hilaire 1812) em um parque urbano no sul do estado de Minas Gerais. Foram observados indivíduos interagindo durante o forrageio e deslocamento. A associação de indivíduos das duas espécies pode ser explicada devido à baixa qualidade do fragmento florestal, pois pode aumentar as chances de obter recursos alimentares e configura uma estratégia de diluição de contra-ataques de predadores.

Evaluating Thermal Infrared Drone Flight Parameters on Spider Monkey Detection in Tropical Forests.

Geoffroy's spider monkeys, an endangered, fast-moving arboreal primate species with a large home range and a high degree of fission-fusion dynamics, are challenging to survey in their natural habitats. Our objective was to evaluate how different flight parameters affect the detectability of spider monkeys in videos recorded by a drone equipped with a thermal infrared camera and examine the level of agreement between coders. We used generalized linear mixed models to evaluate the impact of flight speed (2, 4, 6 m/s), flight height (40, 50 m above ground level), and camera angle (-45°, -90°) on spider monkey counts in a closed-canopy forest in the Yucatan Peninsula, Mexico. Our results indicate that none of the three flight parameters affected the number of detected spider monkeys. Agreement between coders was "substantial" (Fleiss' kappa coefficient = 0.61-0.80) in most cases for high thermal-contrast zones. Our study contributes to the development of standardized flight protocols, which are essential to obtain accurate data on the presence and abundance of wild populations. Based on our results, we recommend performing drone surveys for spider monkeys and other medium-sized arboreal mammals with a small commercial drone at a 4 m/s speed, 15 m above canopy height, and with a -90° camera angle. However, these recommendations may vary depending on the size and noise level produced by the drone model.

A 3D-Printed helmet for precise and repeatable neuromodulation targeting in awake non-human primates.

The application of non-invasive brain stimulation (NIBS) in non-human primates (NHPs) is critical for advancing understanding of brain networks and developing treatments for neurological diseases. Improving the precision of targeting can significantly enhance the efficacy of these interventions. Here, we introduce a 3D-printed helmet designed to achieve repeatable and precise neuromodulation targeting in awake rhesus monkeys, eliminating the need of head fixation. Imaging studies confirmed that the helmet consistently targets the primary motor cortex (M1) with a margin of error less than 1 mm. Evaluations of stimulation efficacy revealed high resolution and stability. Additionally, physiological evaluations under propofol anesthesia showed that the helmet effectively facilitated the generation of recruitment curves for motor area, confirming successful neuromodulation. Collectively, our findings present a straightforward and effective method for achieving consistent and precise NIBS targeting in awake NHPs, potentially advancing both basic neuroscience research and the development of clinical neuromodulation therapies.

Age-related physiological dysregulation progresses slowly in semi-free-ranging chimpanzees.

Background and objectives: Lifestyle has widespread effects on human health and aging. Prior results from chimpanzees (Pan troglodytes), one of humans' closest evolutionary relatives, indicate that these lifestyle effects may also be shared with other species, as semi-free-ranging chimpanzees fed a naturalistic diet show healthier values in several specific health biomarkers, compared with their sedentary, captive counterparts. Here, we examined how lifestyle factors associated with different environments affect rates of physiological aging in closely related chimpanzees. Methodology: We compared physiological dysregulation, an index of biological aging, in semi-free-ranging chimpanzees in an African sanctuary versus captive chimpanzees in US laboratories. If the rate of aging is accelerated by high-calorie diet and sedentism, we predicted greater age-related dysregulation in the laboratory populations. Conversely, if costs of a wild lifestyle accelerate aging, then semi-free-ranging chimpanzees at the sanctuary, whose environment better approximates the wild, should show greater age-related dysregulation. We further tested whether dysregulation differed based on sex or body system, as in humans. Results: We found that semi-free-ranging chimpanzees showed lower overall dysregulation, as well as lower age-related change in dysregulation, than laboratory chimpanzees. Males experienced lower dysregulation than females in both contexts, and the two populations exhibited distinct aging patterns based on body system. Conclusions and implications: Our results support the conclusion that naturalistic living conditions result in healthier aging in chimpanzees. These data provide support for the proposal that lifestyle effects on human health and aging are conserved from deeper into our evolutionary history.

Gastrointestinal Parasites in Non-Human Primates in Zoological Gardens in Northern Italy.

Non-human primates (NHPs) host a variety of helminth and protist parasites that are able to cause infection in humans. Gastrointestinal parasites in NHPs living in two zoological gardens of Northern Italy were studied. An total of 96 faecal pools were collected from 26 groups of NHPs. The mini-Flotac method was applied to fecal samples to detect gastrointestinal helminthiases, while the detection of the protists Cryptosporidium spp., Blastocystis sp. and Giardia duodenalis was performed by targeting SSU rRNA through nested PCR and real-time PCR; they were further studied by sequencing the same gene for Blastocystis and ßgiardine and triosephosphate isomerase (TPI) genes for Giardia. Twenty-two out of the 96 examined fecal pools (22.9%) were positive for one or more helminth species, including Hymenolepis diminuta, Trichurid, Capillariid and Strongylid eggs. All samples were negative for Cryptosporidium spp., while 16/26 (61.5%) animals were positive for G. duodenalis in the real-time PCR; the sequences obtained assigned them all to sub-assemblage BIV. Blastocystis sp. was detected in 22/26 of the NHPs (84.6%); molecular analyses attributed the isolates to ST 4, allele 92. Analyses of the feces of sympatric rats revealed the presence of the same allele, as well as of Hymenolepis diminuta eggs, raising concern about their role as parasite reservoirs in the facilities.

Evaluating Methods for the Prediction of Cell Type-Specific Enhancers in the Mammalian Cortex.

Identifying cell type-specific enhancers in the brain is critical to building genetic tools for investigating the mammalian brain. Computational methods for functional enhancer prediction have been proposed and validated in the fruit fly and not yet the mammalian brain. We organized the 'Brain Initiative Cell Census Network (BICCN) Challenge: Predicting Functional Cell Type-Specific Enhancers from Cross-Species Multi-Omics' to assess machine learning and feature-based methods designed to nominate enhancer DNA sequences to target cell types in the mouse cortex. Methods were evaluated based on in vivo validation data from hundreds of cortical cell type-specific enhancers that were previously packaged into individual AAV vectors and retro-orbitally injected into mice. We find that open chromatin was a key predictor of functional enhancers, and sequence models improved prediction of non-functional enhancers that can be deprioritized as opposed to pursued for in vivo testing. Sequence models also identified cell type-specific transcription factor codes that can guide designs of in silico enhancers. This community challenge establishes a benchmark for enhancer prioritization algorithms and reveals computational approaches and molecular information that are crucial for the identification of functional enhancers for mammalian cortical cell types. The results of this challenge bring us closer to understanding the complex gene regulatory landscape of the mammalian brain and help us design more efficient genetic tools and potential gene therapies for human neurological diseases.

Multimodal sexual signals are not precise indicators of fertility in female Kinda baboons.

Female fertility signals are found across taxa, and the precision of such signals may be influenced by the relative strength of different sexual selection mechanisms. Among primates, more precise signals may be found in species with stronger direct male-male competition and indirect female mate choice, and less precise signals in species with stronger indirect male-male competition (e.g. sperm competition) and direct female mate choice. We tested this hypothesis in a wild population of Kinda baboons in Zambia, combining data on female signals with reproductive hormones (estrogen and progesterone metabolites) and intra- and inter-cycle fertility. We predicted that Kinda baboons will exhibit less precise fertility signals than other baboon species, as they experience weaker direct and stronger indirect male-male competition. The frequency of copulation calls and proceptive behavior did not vary with hormones or intra- or inter-cycle fertility in almost all models. Sexual swelling size was predicted by the ratio of estrogen to progesterone metabolites, and was largest in the fertile phase, but differences in size across days were small. Additionally, there was variability in the timing of ovulation relative to the day of sexual swelling detumescence across cycles and swelling size did not vary with inter-cycle fertility. Our results suggest that female Kinda baboon sexual swellings are less precise indicators of fertility compared to other baboon species, while signals in other modalities do not reflect variation in intra- and inter-cycle fertility. Female Kinda baboon sexual signals may have evolved as a strategy to reduce male monopolizability, allowing for more female control over reproduction by direct mate choice.

Commentary: Early-in-life Isoflurane Exposure Alters Resting-State Functional Connectivity in Juvenile Non-human Primates - a Role for Neuroinflammation?

The concern about anesthesia-induced developmental neurotoxicity (AIDN) in infants and young children arises from animal studies indicating potential long-term neurobehavioral impairments following early-in-life anesthesia exposure. While initial clinical studies provided ambiguous results, recent prospective assessments in children indicate associations between early-in-life anesthesia exposure and later behavioral alterations. Ethical constraints and confounding factors in clinical studies pose challenges in establishing a direct causal link and in investigating its mechanisms. This commentary on a recent study in non-human primates (NHPs) focuses on exploring the role of neuroinflammation and alterations in brain functional connectivity in the behavioral impairments following early-in-life anesthesia exposure. In juvenile NHPs, chronic astrogliosis in the amygdala correlates with alterations in functional connectivity between this area with other regions of the brain and with the behavioral impairments, suggesting a potential mechanism for AIDN. Despite acknowledging the study's limitations, these findings emphasize the need for further research with larger cohorts to confirm these associations and to establish a causal link between the neuroinflammation and the behavioral alterations associated with early-in-life anesthesia exposure.

SARS-CoV-2 infection perturbs the gastrointestinal tract and induces modest microbial translocation across the intestinal barrier.

SARS-CoV-2 infects via the respiratory tract, but COVID-19 includes an array of non-respiratory symptoms, among them gastrointestinal (GI) manifestations such as vomiting and diarrhea. Here we investigated the GI pathology of SARS-CoV-2 infections in rhesus macaques and humans. Macaques experienced mild infection with USA-WA1/2020 and shed viral RNA in the respiratory tract and stool, including subgenomic RNA indicative of replication in the GI tract. Intestinal immune cell populations were disturbed, with significantly fewer proliferating (Ki67+) jejunal B cells in SARS-CoV-2-infected macaques than uninfected ones. Modest translocation of bacteria/bacterial antigen was observed across the colonic epithelium, with a corresponding significant increase in plasma soluble CD14 (sCD14) that may be induced by LPS. Human plasma demonstrated significant decreases in interleukin (IL)-6 and sCD14 upon recovery from COVID-19, suggesting resolution of inflammation and response to translocated bacteria. sCD14 significantly positively correlated with zonulin, an indicator of gut barrier integrity, and IL-6. These results demonstrate that GI perturbations such as microbial translocation can occur in even mild SARS-CoV-2 infections and may contribute to the COVID-19 inflammatory state.IMPORTANCEThis study investigates gastrointestinal (GI) barrier disruption in SARS-CoV-2 infections and how it may contribute to disease. We observed bacteria or bacterial products crossing from the colon interior (the lumen) to the lamina propria during SARS-CoV-2 infection in macaques. Bacteria/bacterial products are tolerated in the lumen but may induce immune responses if they translocate to the lamina propria. We also observed a significant increase in soluble CD14, which is associated with an immune response to bacterial products. In addition, we observed that humans recovering from COVID-19 experienced a significant decrease in soluble CD14, as well as the inflammatory marker interleukin (IL)-6. IL-6 and sCD14 correlated significantly across macaque and human samples. These findings suggest that SARS-CoV-2 infection results in GI barrier disruption that permits microbial translocation and a corresponding immune response. These findings could aid in developing interventions to improve COVID-19 patient outcomes.

First record of a mixed species association between Hatinh langur (Trachypithecus hatinhensis) and red-shanked douc (Pygathrix nemaeus).

In primates, mixed species associations are not common occurrences, and have been linked to both ecological and anthropogenic factors. We present camera-trapping records of a mixed association between two primates, the Hatinh langur (Trachypithecus hatinhensis) and red-shanked douc (Pygathrix nemaeus) and discuss possible hypotheses for this occurrence. To our knowledge, this is the first evidence of such an association in the wild of these two threatened primates, and thus contributes to our limited ecological knowledge of the species.

Endocranial shape variation and allometry in Euarchontoglires.

While brain size in primates and their relatives within Euarchontoglires is well-studied, less research has examined brain shape, or the allometric trajectories that underlie the relationship between size and shape. Defining these patterns is key to understanding evolutionary trends. 3D geometric morphometric analyses of endocranial shape were performed on 140 species of extant euarchontoglirans using digital cranial endocasts. Principal component analyses on Procrustes shape variables show a clear phylogenetic pattern in endocranial shape, supported by an ANOVA which identified significant differences in shape among several groups (e.g., Platyrrhini, Strepsirrhini, Scandentia, Rodentia, and Lagomorpha). ANOVAs of shape and size also indicate that allometry has a small but significant impact on endocranial shape across Euarchontoglires, with homogeneity of slopes tests finding significant differences in the scaling relationship between shape and size among these same groups. While most of these clades possess a distinct endocranial morphotype, the highly derived platyrrhines display the strongest relationship between size and shape. Rodents show the most diversity in endocranial shape, potentially attributed to their comparatively weak relationship between shape and size. These results suggest fundamental differences in how shape and size covary among Euarchontoglires, which may have facilitated the adaptive radiations that characterize members of this group.

Comparative morphology in the context of facial reduction: Modularity in primate, dog, and bat crania.

Biological variation in the mammalian skull is the product of a series of factors including changes in gene expression, developmental timing, and environmental pressures. When considering the diversity of extant mammalian crania, it is important to understand these mechanisms that contribute to cranial growth and in turn, how differences in cranial morphology have been attained. Various researchers, including Dr. Sue Herring, have proposed a variety of mechanisms to explain the process of cranial growth. This work has set the foundation on which modern analysis of craniofacial morphology happens today. This study focused on the analysis of modularity in three mammalian taxa, all of which exhibit facial reduction. Specifically, we examined facial reduction as a morphological phenomenon through the use of two-module and six-module modularity hypotheses. We recorded three-dimensional coordinate data for 55 cranial landmarks that allowed us to analyze differences in cranial shape in these three taxa (primates n = 88, bats n = 64, dogs n = 81). When assessing modularity within the two-module modularity hypothesis specifically, dogs exhibited the lowest levels of modularity, while bats and primates both showed a slightly more modular covariance structure. We further assessed modularity in the same sample using the Goswami six-module model, where again dogs exhibited a low degree of modularity, with bats and primates being more moderate. We then broke the sample into subsets by analyzing each morphotype separately. We hypothesized that the modularity would be more pronounced in the brachycephalic morphotype. Surprisingly, we found that in brachycephalic dogs, normocephalic dogs, brachycephalic primates, and normocephalic primates, there was a moderate degree of modularity. Brachycephalic bats had a low degree of modularity, while normocephalic bats were the most modular group observed in this study. Based on these results, it is evident that facial reduction is a complex and multifaceted phenomenon with unique morphological changes observed in each of the three taxa studied.

Diagnostic features of metastatic endometrioid carcinoma in a captive black-tufted marmoset (Callithrix penicillata).

A captive marmoset developed metastatic endometrioid carcinoma (EnC), a rare uterine tumor in non-human primates (NHPs). The neoplasm showed marked microscopical malignant and tubulopapillary aspects, immunopositivity for pan-cytokeratin, CK7, estrogen receptor, and a high mitotic index (Ki-67). These features may contribute to the diagnosis and therapeutics of EnC in NHPs.

More allogrooming is followed by higher physiological stress in wild female baboons.

Social bonds increase fitness in a range of mammals. One pathway by which social bonds may increase fitness is by reducing the exposure to physiological stress, i.e. glucocorticoid (GC) hormones, that can be detrimental to health and survival. This is achieved through downregulating hypothalamic-pituitary-adrenal (HPA)-axis activity. Indeed, long-term measures of social (grooming) bonds are often negatively correlated with HPA-axis activity. However, the proximate role of physical touch through allogrooming remains an open question in the sociality-health-fitness debate. Demonstrating the potential anxiolytic benefits of grooming in the wild is hindered by methodological limitations. Here, we match accelerometer-identified grooming in wild female chacma baboons (Papio ursinus) to non-invasive faecal GC metabolite concentrations (fGCs). Consistent with previous work, we found a negative (but statistically non-significant) overall relationship between individual averaged fGCs and grooming rates. However, when time-matching grooming to fGCs, we found that both more giving and receiving grooming were followed by higher fGCs. This upregulation of HPA-axis activity suggests that maintaining social bonds (and its ultimate fitness benefits) may come at a shorter-term physiological cost. This finding sheds new light on a ubiquitous social behaviour typically considered 'relaxing' and suggests that sociopositive contact can trigger physiological stress.

A cross-sectional survey of Blastocystis sp. and Dientamoeba fragilis in non-human primates and their caregivers in Czech zoos.

Intestinal protists in the gut microbiome are increasingly studied, but their basic epidemiology is not well understood. We explored the prevalence, genetic diversity, and potential zoonotic transmission of two protists colonizing the large intestine - Blastocystis sp. and Dientamoeba fragilis - in 37 species of non-human primates (NHPs) and their caregivers in six zoos in the Czech Republic. We analyzed 179 fecal samples (159 from NHPs, 20 from humans) by qPCR. Blastocystis sp. was detected in 54.7% (98/179) of samples, in 24 NHP species and in 57.2% of NHP samples (prevalence ranged between 36 and 80%), and in 35% of human samples (prevalence ranged between 0 and 67%). Using next generation amplicon sequencing, nine Blastocystis subtypes (ST1-ST5, ST7, ST8, and two novel subtypes) were identified. The two new Blastocystis subtypes (named ST47 and ST48) were described using Nanopore sequencing to produce full-length reference sequences of the small subunit ribosomal RNA gene. Some subtypes were shared between NHPs and their caregivers, suggesting potential zoonotic transmission. Mixed subtype colonization was frequently observed, with 52% of sequenced samples containing two or more subtypes. Dientamoeba was found only in NHPs with a prevalence of 6%. This study emphasizes the critical role of molecular diagnostics in epidemiological and transmission studies of these protists and calls for further research to better understand their impact on public health.

Landscape-level habitat connectivity of large mammals in Chitwan Annapurna Landscape, Nepal.

The populations of many species of large mammals occur in small isolated and fragmented habitat patches in the human-dominated landscape. Maintenance of habitat connectivity in the fragmented landscapes is important for maintaining a healthy population of large mammal. This study evaluated the landscape patches and their linkages on two carnivores (leopard and Himalayan black bear) and seven prey species (northern red muntjac, chital, sambar, wild pig, Himalayan goral, rhesus macaque, and langur) between Chitwan National Park (CNP) and Annapurna Conservation Area (ACA) by using the least-cost path (LCP) approach and the Linkage Mapper tool in ArcGIS. A total of 15 habitat patches (average area 26.67 ± 12.70 km2) were identified that had more than 50% of the total studied mammals. A weak relation among the habitat patches was found for chital and sambar (Cost-weighted distance [CWD]: Euclidean distance EucD >100), showed poor connectivity between the habitat patches, while ratio of CWD and EucD was low (i.e., low LCP) between majority of the patches for muntjac, wild pig and leopard hence had potential functional connectivity along the landscape. Similarly, low LCP between the habitat patches located in the mid-hills was observed for Himalayan goral and Himalayan black bear. Furthermore, the multi-species connectivity analysis identified the potential structural connectivity between the isolated populations and habitat patches. Therefore, these sites need to be considered connectivity hotspots and be prioritized for the conservation of large mammals in the landscape.

Effects of chronic naltrexone treatment on relapse-related behavior and neural responses to fentanyl in awake nonhuman primates.

Naltrexone, an opioid antagonist that blocks the reinforcing properties of opioid agonists, is often prescribed to preclude relapse to opioid use disorder (OUD) following detoxification. However, few laboratory studies have directly investigated the ability of naltrexone to alter relapse-inducing effects of opioid agonists, including their priming strength in reinstatement studies and their impact in brain regions known to be involved in drug-induced reinforcement in MRI studies. Here we directly address this issue by investigating the effects of continuous exposure to naltrexone on 1) fentanyl-induced reinstatement of drug-seeking behavior, 2) fentanyl-induced patterns of blood oxygenation level dependent (BOLD) activation in the nucleus accumbens (NAcc), and 3) fentanyl-induced changes in NAcc functional connectivity (FC) in awake non-human primates that are engaged in ongoing opioid self-administration studies. We found that naltrexone antagonizes the priming strength of fentanyl as shown by a rightward shift in its reinstatement dose-effect curve and that naltrexone surmountably antagonizes the BOLD response induced by fentanyl. However, while naltrexone also countered fentanyl's effects on NAcc FC, the effects were not surmounted by a higher dose of fentanyl. Together, these data suggest that, in contrast to naltrexone's modulation of fentanyl's effects on behavior and BOLD responses, their interactive effects on FC between multiple brain regions do not reflect their receptor-mediated activity. Additionally, we demonstrated opposing effects in the absence and presence of naltrexone on NAcc FC at baseline (i.e., in the absence of any fentanyl prime) suggesting that naltrexone alters FC at baseline, even though naltrexone appears behaviorally silent in the absence of an agonist prime. Together these data provide additional insight into ways in which naltrexone interacts with opioid agonists, both behaviorally and in the brain. Further understanding the effects of opioid agonists on patterns of FC could help elucidate our understanding of the neural processes that contribute to the initiation of and relapse to opioid-seeking behavior in OUD.

An update on nonhuman primate usage for drug and vaccine evaluation against filoviruses.

INTRODUCTION: Due to their faithful recapitulation of human disease, nonhuman primates (NHPs) are considered the gold standard for evaluating drugs against Ebolavirus and other filoviruses. The long-term goal is to reduce the reliance on NHPs with more ethical alternatives. In silico simulations and organoid models have the potential to revolutionize drug testing by providing accurate, human-based systems that mimic disease processes and drug responses without the ethical concerns associated with animal testing. However, as these emerging technologies are still in their developmental infancy, NHP models are presently needed for late-stage evaluation of filovirus vaccines and drugs, as they provide critical insights into the efficacy and safety of new medical countermeasures. AREAS COVERED: In this review, the authors introduce available NHP models and examine the existing literature on drug discovery for all medically significant filoviruses in corresponding models. EXPERT OPINION: A deliberate shift toward animal-free models is desired to align with the 3Rs of animal research. In the short term, the use of NHP models can be refined and reduced by enhancing replicability and publishing negative data. Replacement involves a gradual transition, beginning with the selection and optimization of better small animal models; advancing organoid systems, and using in silico models to accurately predict immunological outcomes.

Systematic review and meta-analysis on seroprevalence of leptospirosis in non-human primates worldwide.

Leptospirosis is a zoonotic disease whose transmission is linked to multiple factors involving the interface between animals, humans, and the environment. This disease is of great importance for public health, as it profoundly affects the health aspects of the population and animals. Considering the importance of non-human primates in this epidemiological chain, the objective of this research was to conduct a systematic literature review with meta-analysis, providing information on leptospirosis in non-human primates (NHPs) and an update on the infection situation in Brazil and other countries. Thus, a search was performed in five databases, initially finding 3332 studies, of which 32 met the eligibility criteria and were used for the systematic review. According to them, the most prevalent serogroup in non-human primates was Icterohaemorrhagiae, which is adapted to rodents as primary hosts. A wide distribution of the infection was found in the regions of both wild and captive animals. Through meta-analysis, the seroprevalence rate of leptospirosis in non-human primates was 27.21% (CI 17.97-38.95%). Cochran's Q test (p < 0.01) identified heterogeneity between studies, classified as high by the Higgins and Thompson test (I2 = 92.4%). Therefore, seroepidemiological and Leptospira isolation studies in non-human primates are important to investigate and monitor the suspected impact of these species as maintainers or transmitters of the pathogen to humans and other wild and domestic animals, in addition to demonstrating the need for standardization related to control and prevention measures.

Lateralization of Feeding Behaviour in White-Fronted Lemur (Eulemur albifrons) and Ring-Tailed Lemur (Lemur catta) in Captivity.

INTRODUCTION: Functional cerebral asymmetry is reflected in the lateralization of some behavioural patterns in many vertebrate species. In primates, behavioural lateralization has been related to both life style and age and sex, and it affects behaviours such as feeding and other tasks that require precision movements. METHODS: We have studied feeding lateralization concerning the use of right and left hand to take the food in two species of lemurs in captivity, the mainly arboreal white-fronted lemur and the more terrestrial ring-tailed lemur, taking also account the age and the sex of the individuals. We calculated for each individual the hand preference (if it was the case) by means of z scores, and the strength of such preference using the handedness index (HI). Finally, we determined for each species the existence of right/left bias at the group level with the t Student test. RESULTS: Half of the white-fronted lemurs (7 of 14) showed lateralization in feeding, while only a few ring-tailed lemurs (3 of 19) showed it. In the first species, a light bias seems to emerge (5 individuals used mostly the right hand for taking the food, while only 2 used mainly the left hand), while in the second species no bias could really be appreciated. CONCLUSION: Feeding lateralization was more accentuated in white-fronted lemur, in which a light bias towards the use of the right hand seems to be evidenced. No clear effect of age and sex on the presence and direction of lateralization could be evidenced. The results somehow contrast with what the postural theory of lateralization postulates about the preferential use of the right hand in terrestrial species.