Natural ecosystems are severely disrupted by human activities. Our interactions with wildlife are intensifying and promoting zoonosis. Humans and chimpanzees can harbour and transmit pathogens to each other. The aim of this study is to improve our knowledge of the diversity of gastrointestinal parasites in Fongoli chimpanzees. This is a habituated group that has been monitored over the long term and whose members have all been identified. During the period from 22 February to 11 March 2022, we monitored them daily to collect fresh stool samples in a non-invasive manner. A total of 17 individuals were sampled for 39 faeces samples collected and fixed in 10 % formalin. In the laboratory, we performed a coproscopical analysis of the fixed faeces using flotation and sedimentation methods. The parasite diversity included six protozoa (Troglodytella spp., Troglocorys spp., Entamoeba coli, Entamoeba spp., an unidentified ciliate, and Coccidia) and six helminths (Enterobius spp., Strongyloides spp., Dicrocoelium spp., Ascaris spp., Spirurids, and Strongylids). We found protozoa in all individuals and helminths in 70 % of individuals. We found an average of 6 ± 1.41 types of gastrointestinal parasites, including 1.47 ± 1.07 helminths per individual. Chimpanzees in Fongoli harbour a significant diversity of intestinal parasites, some of which are common to humans and have zoonotic potential.
This paper reports long-term data on the seasonality of sightings of Ucayali bald uakaris, Cacajao ucayalii at the Estación Biológica Quebrada Blanco (EBQB). Sightings were most common during the drier parts of the year and rarer during the rainy season. This suggests that the C. ucayalii groups travel long distances and seasonally move (migrate) between different parts of presumably large home ranges and between different habitats (terra firme forest, Amazon floodplain forest). Areas to protect this Neotropical primate must be large enough to allow for sufficient seasonal access to these vegetation types.
Between May 2014 and March 2016, 22 groups of Mount Kenya guerezas (Colobus guereza kikuyuensis Lönnberg, 1912) were reintroduced in Karura Forest, Kenya. To assess the success of the reintroduction, we conducted monthly censuses over 8 years (2016–2023). We determined group size and composition of the reintroduced population. During the censuses, we recorded instances of births, deaths (disappearance), dispersal from natal groups, and the habitat types where groups established home ranges. A total of 14 of the reintroduced groups settled along the riverine zones. Over the years, we recorded an annual increase in the number of births and group size, indicating successful adaptation of the reintroduced primates. Coming from a degraded source habitat, the primary cause of death was related to arboreality adaptation (23 %), and only one case of infanticide during a group takeover was recorded. Group fusion was not observed; however, seven groups with more than two adult males began splitting in 2019. By December 2023, 109 births had been recorded, and groups increased to 31 due to natal dispersal. Our results demonstrate that C. guereza kikuyuensis reintroduction to Karura Forest was a success.
Water is an essential nutrient for living beings and is fundamental to metabolic processes. Under free-living conditions, primate individuals can use different strategies, skills, and resources to access water. Here, we report on observations of water consumption in Ateles chamek and Sapajus apella; describe the environmental conditions in which such events were observed, as well as the behavior of the individuals; and compare these observations with similar records in neotropical primates. Water consumption was observed during primate surveys in a forest fragment of approximately 52 ha bordered by the Jaru River, located southwest of the Brazilian Amazon, Vale do Paraíso municipality, state of Rondônia, Brazil. To access water, individuals of A. chamek used their tails, whereas S. apella used a leaf as a tool. Our observations suggest that tree holes may be important water sources for primates in forest fragments and that individuals of different species use different strategies to collect water from tree holes. Access and consumption strategies are directly associated with different cognitive skills and behaviors, which may include using tools, as in the case of capuchins. As water consumption records are limited, these findings highlight the need for continuous reporting to better understand water acquisition. Such reports are especially needed in the context of fragmented and degraded habitats, where water availability is affected by edge effects and the reduction in both fleshy fruits and moisture, which are important for primate species.
Intersexual dominance relationships in virtually all lemur species have been reported to be female-biased. Although a claim of male dominance in greater bamboo lemurs (Prolemur simus) which was not supported by data is unusual against this background, it is in line with recent studies on other lemur species that suggest the existence of a continuum of intersexual dominance relationships. We therefore studied the details of agonistic interactions among adults of one captive group of P. simus at Cologne Zoo. This very preliminary study confirmed male-biased dominance because the adult male of the study group won all agonistic interactions with all three adult females, and the male was never dominated by any of the females. This result raises several interesting questions about the mechanisms and evolution of intersexual dominance relationships in group-living lemurs and should encourage similar future studies of additional groups of this species – ideally in the wild.
In the context of a global research initiative called ManyPrimates, scientists from around the world collaborated to collect data aimed at comparing the ability of various primate species to delay gratification. Our contribution to this project involved collecting data from long-tailed macaques (Macaca fascicularis). Our findings indicated that these macaques rarely opted to exchange a given food item for a larger food reward at a later time. However, we suspected that the experimental protocol might not accurately capture the macaques' actual capacity to delay gratification. Specifically, possessing a highly desirable food item might discourage the monkeys' participation in food exchange and delay-of-gratification tasks. To explore whether this potential mental distraction was affecting their performance, we conducted experiments on six long-tailed macaques under two different conditions. In these conditions, we examined how the value of the exchange item influenced the frequency of exchanges. In one condition, subjects received a high-value food item, while in the other, they received a low-value food item, both of which could be exchanged for three high-value food items. When we reduced the value of the exchange item, the long-tailed macaques displayed significantly improved abilities to delay gratification within the exchange task. These findings strongly suggest that the possession of a high-value item significantly contributed to the low performance of these monkeys in the original delay-of-gratification exchange protocol and raise the question of which performance reflects the monkeys' underlying delay-of-gratification competence more adequately.
The so-called arc of deforestation is a major agricultural and industrial frontier in southern Amazonia and northern Cerrado of Brazil. As arboreal mammals, the primates in this region are therefore threatened by forest loss and fragmentation. At the same time, knowledge about the taxonomic diversity and distribution ranges of these taxa is incomplete, which might hamper efficient conservation measurements. New species have been recently discovered in this region, and their ranges remain imprecise because only a few occurrence records are available for each species. Here we present 192 new records of 22 species and subspecies of Alouatta, Aotus, Ateles, Cebus, Chiropotes, Lagothrix, Leontocebus, Pithecia, Plecturocebus, Saimiri, and Sapajus, collected in 56 different localities during 10 field expeditions across the arc of deforestation between 2015 and 2018. Based on these new records, we extend the ranges of Alouatta puruensis, Ateles chamek, and Saimiri collinsi; identify potential hybridization zones between A. puruensis and A. discolor, and between At. chamek and At. marginatus; redefine the range of Plecturocebus moloch; and clarify the ranges of P. baptista and P. hoffmannsi. Moreover, these results and the dataset are valuable for further research on, for example, species distribution and habitat use modeling, for assessing species extinction risks, and for supporting efforts for the conservation of species increasingly threatened on a global deforestation frontier.
Two cystadenomas and one solid adenoma of the thyroid gland in a 27-year-old female African green monkey (Chlorocebus aethiops) are described here. Histologically, the solid adenoma was classified as a well-defined solid follicular adenoma of microfollicular type. The solid adenoma was positive for thyroglobulin in immunohistochemistry staining, whereas the cystadenomas stained positive for both thyroglobulin and calcitonin. No evidence of excess hormone production related to the tumor presence was detected.
The size and density of a population are essential parameters in primate ecology and conservation. Such information, however, is still scarce for many forest primate species. The Djaffa Mountains guereza (Colobus guereza gallarum) is an endemic Ethiopian taxon for which data about its distribution and population size are missing. Therefore, we aimed to estimate the abundance and population size of the Djaffa Mountains guereza in four forests in the Ahmar Mountains southeast of the Ethiopian Rift Valley. We conducted line-transect surveys in the forests. Within an area of 183 km2, we sampled 19 transects covering a distance of 75.9 km. We encountered 73 guereza clusters which most likely represent social groups. Since the detection distances and cluster sizes did not differ among the four forests, we applied a conventional distance sampling (CDS) model and estimated a population density of 20.6 clusters per square kilometer, i.e., 109.6 individuals per square kilometer or 20 061 individuals within the complete study area. This abundance is relatively high compared to other C. guereza taxa. However, given that the habitat and population of C. g. gallarum are already highly fragmented, further monitoring of the population and exploration of the possibilities of reconnecting its habitat should be priorities for the conservation of this taxon.
Currently, 15 species of Amazon marmosets (genus Mico) are known to science. The Amazon marmosets occur primarily in southern Brazilian Amazonia, the arc of deforestation, and are among the least studied primates of the neotropics. This is particularly the case for M. acariensis and M. chrysoleucos, both endemic to the Aripuanã–Sucundurí interfluve, south-central Amazonia. Mico acariensis was not studied beyond the species description, and the only information currently available is the pelage colouration of the holotype, inferred coordinates of the type locality, and a field report with two additional localities of occurrence. Regarding M. chrysoleucos, in addition to the species description, there are taxonomic reviews, the report of a second occurrence record, and a study on the species range. We provide here new occurrence records that extend the distribution of M. chrysoleucos; provide new records for and update the distribution of M. acariensis; and propose the existence of a hybrid zone in the Aripuanã–Sucundurí interfluve, i.e. around the known distribution boundaries of M. acariensis, M. chrysoleucos, and M. melanurus, and we also discuss habitat use patterns of Amazon marmosets.
In 2020, a new subspecies was described in the Cercopithecus mitis complex, the Manyara monkey C. m. manyaraensis, Butynski & De Jong, 2020. The internal taxonomy of this species complex is still debated, and the phylogenetic relationships among the taxa are unclear. Here we provide the first mitochondrial sequence data for C. m. manyaraensis to determine its position within the mitochondrial phylogeny of C. mitis. This subspecies clusters within the youngest (internal divergences between 1.01 and 0.42 Ma) of three main taxonomic clades of C. mitis. Its sister lineages are C. m. boutourlinii (Ethiopia), C. m. albotorquatus (Kenya and Somalia), C. m. albogularis (Kenya and Tanzania), and C. m. monoides (Tanzania and Mozambique). In general, the phylogenetic tree of C. mitis based on mitochondrial sequence data indicates several paraphyletic relationships within the C. mitis complex. As in other African cercopithecines (e.g. Papio and Chlorocebus), these data are suitable for reconstructing historic biogeographical patterns, but they are only of limited value for delimitating taxa.
Howler monkeys Alouatta are almost exclusively arboreal. They will, however, occasionally descend to the forest floor to conduct geophagy at clay licks if these are present within their home range. They do this to incorporate certain minerals into their diet and/or for detoxification purposes. Clay licks are risky areas however, especially for arboreal mammals, as visiting them requires the monkeys to leave the safety of the trees. This has been confirmed by observed predation attempts on howler monkeys by large felines at clay licks. We report an additional risk for howler monkeys descending to the forest floor that has not previously been considered, namely potential attacks by collared peccaries Dicotyles tajacu. Camera traps were placed at three different clay licks in the Taricaya Ecological Reserve, located in the southeastern Peruvian Amazon, to monitor the fauna within the reserve. On 4 June 2017, the camera traps registered a lethal attack on a howler monkey by a group of collared peccaries at one of the clay licks.
Estimating population densities and their trends over time is essential for understanding primate ecology and for guiding conservation efforts. From 2011 through to 2019, we counted two guenon species during seasonal road transect surveys in Lake Manyara National Park: the Tanzania-endemic Manyara monkey Cercopithecus mitis manyaraensis (International Union for Conservation of Nature and Natural Resources, IUCN, Red List category of "endangered") and the vervet monkey Chlorocebus pygerythrus (Red List category of "least concern"). To account for imperfect detectability, we analysed the data in a line distance sampling framework, fitted species-specific detection functions, and subsequently estimated seasonal densities. To test for seasonal differences and yearly trends in the species-specific density estimates, we fitted generalized additive models. Seasonal point density estimates fluctuated considerably during the 9 years (2011-2019) of our study, ranging from 3 to 29 individuals km - 2 for Manyara monkeys and from 19 to 83 individuals km - 2 for vervet monkeys. Densities of both taxa did not differ seasonally, and we did not detect marked directional population trends. Our study illustrates the utility and limitations of line distance sampling for long-term primate monitoring. Beyond informing primate ecology and management, our results highlight the conservation importance of Lake Manyara National Park for primate conservation.
Peru has the highest diversity of members of the tamarin genus Leontocebus (Callitrichidae). However, for a number of taxa from this genus the distributional ranges are still not well known. In this paper we provide evidence for the extension of the southern range of Leontocebus fuscicollis fuscicollis to the right bank of the Río Abujao, south of which it is replaced by Leontocebus weddelli weddelli.
Abstract Alfaxan® (alfaxalone) is a steroid general anesthetic widely used in veterinary medicine for induction and maintenance of anesthesia in several species. While the use of alfaxalone in veterinary practice has several benefits compared to the use of other anesthetic agents, the fact that it is derived from progesterone may confound the measurement of the latter in the blood of animals under alfaxalone treatment. In the present case study, we report the measurement of serum progesterone in an individual common marmoset (Callithrix jacchus) during five ovarian cycles in which luteolysis was induced by PGF2 α . Blood samples were usually taken from the awake animal with the exception of the fifth cycle in which the sample was collected under alfaxalone anesthesia in connection with a tooth extraction. In contrast to the previous four cycles in which luteolysis resulted in the expected marked decrease in progesterone concentrations, the – apparent – progesterone level in the cycle under alfaxalone treatment remained unexpectedly high. Cross-reactivity of the non-specific antibody used in the progesterone assay with alfaxalone most likely explains this finding.
Abstract Fur rubbing, i.e. rubbing a substance or an object into the pelage, has been described in numerous Neotropical primate species, including species of titi monkeys, but it seems to be a rare behaviour. Here we describe a fur rubbing event in a wild coppery titi monkey (Plecturocebus cupreus) with Psychotria sp. (Rubiaceae) leaves observed and videotaped during a field study on vigilance behaviour between September–December 2019 in the Peruvian Amazon. Plants of the genus Psychotria contain a great diversity of secondary metabolites and are often used in traditional medicine. We suggest that the fur rubbing was an act of self-medication. This is the first record of fur rubbing in coppery titi monkeys in almost 4400 h of observation accumulated over more than 20 years.
Abstract. The American Museum of Natural History houses the skin of a tamarin (AMNH 98303) labelled as Saguinus fuscicollis tripartitus. However, the specimen does not match the phenotype of this taxon, now named Leontocebus tripartitus, nor that of any other known species or subspecies of Leontocebus. In this note, we review past taxonomic revisions of the genus Saguinus – revisions that were largely driven by the contentious species or subspecies status of the golden-mantled saddleback tamarin S. fuscicollis tripartitus – and compare the phenotype of AMNH 98303 with those of other tamarins in the same genus to discuss the possible status of this specimen.
Forest edges change micro-environmental conditions, thereby affecting the ecology of many forest-dwelling species. Understanding such edge effects is particularly important for Malagasy primates because many of them live in highly fragmented forests today. The aim of our study was to assess the influence of forest edge effects on activity budgets, feeding ecology, and stress hormone output (measured as faecal glucocorticoid metabolite – fGCM – levels) in wild Verreaux's sifakas (Propithecus verreauxi), a group living, arboreal lemur. We observed five habituated groups: three living in the forest interior and two at an established forest edge. There was no difference in average daily temperatures between edge and interior habitats; however, within the edge site, the average daily temperature incrementally increased over 450 m from the forest edge towards the interior forest of the edge habitat, and the population density was lower at the edge site. Activity budgets differed between groups living in the two microhabitats, with individuals living near the edge spending more time travelling and less time feeding. Groups living near the edge also tended to have smaller home ranges and core areas than groups in the forest interior. In addition, edge groups had elevated average fGCM concentrations, and birth rates were lower for females living in the edge habitat. Combined with lower levels of fruit consumption at the edge, these results suggest that nutritional stress might be a limiting factor for Verreaux's sifakas when living near a forest edge. Hence, Verreaux's sifakas appear to be sensitive to microhabitat characteristics linked to forest edges; a result with implications for the conservation of this critically endangered lemurid species.
