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A review of Minoan frescoes and artefacts suggests interactions with two primate groups in sacred and leisure contexts, respectively. This demonstrates the early exchange of iconography and knowledge of monkeys between the Aegean and North Africa.
Saimiri collinsi is used as an animal model in biotechnology research for conservation of species from the genus Saimiri. However, the development of biotechnologies depends on a proper knowledge of the sperm morphology to understand the basic aspects of sperm physiology, as potential male fertility depends on different cellular sperm structures. With this purpose, this study characterized the micromorphological and ultrastructural characteristics of squirrel monkeys (Saimiri collinsi) sperm using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). SEM electromyography revealed that a normal Saimiri collinsi sperm measures 71.7 ± 0.7 μm with lateral tail insertion, a paddle-shaped flattened head and an acrosome occupying most of the head. TEM also showed that the middle piece is characterized by a central 9 + 2 microtubule axoneme surrounded by nine dense fibres, and that the mitochondria were juxtaposed, forming the mitochondrial sheath. Here we provide the first micromorphological and ultrastructure description of S. collinsi sperm.
The Critically Endangered Peruvian yellow-tailed woolly monkey Lagothrix flavicauda was presumed to only occur in the tropical montane cloud forests between the Marañón and Huallaga rivers in northern Peru. Here we report the discovery of a population to the south of its previously known range, in the Región Junín. During September–December 2018 we carried out transect surveys to record large mammals present near the village of San Antonio in the district of Pampa Hermosa, at 1,287–2,015 m altitude. We recorded five primate species during transect surveys. Lagothrix flavicauda was seen four times, and appeared phenotypically distinct from populations to the north, with notable white patches above each eye and a reduced yellow patch at the end of the tail. The presence of L. flavicauda in Junín extends its known geographical range over 200 km southwards from the closest previously known population in the Huánuco region, and presents a unique opportunity for the conservation of this Critically Endangered species.
Primates are an order of mammals which share a set of traits inherited from a common ancestor that distinguishes them from all other mammals. These derived traits are not all unique to primates and none of the individual traits is shown by all primates. Primates range in body mass from the 30 g Madame Berthe's mouse lemur to around 250 kg for a male Grauer's gorilla. This variation in size is in line with that found in other mammalian orders and is closely associated with what they eat (diet), how they move (locomotion), and their behaviour. In this chapter, I provide a general introduction to the primates and their evolutionary adaptations (traits produced by natural selection for their current function), including their distribution and habitats, adaptations to life in the trees, diet and dietary adaptations, brains and sensory traits, life history and reproduction, behaviour and locomotion, social behaviour and interactions with other species. I then survey the major groups of primates. Throughout the chapter, I highlight terms that are common in the literature but are problematic.
It is our ethical duty to consider the possible consequences of our work and mitigate any risks, such that we avoid harm to the welfare and interests of our study animals, human participants, the environment, and the people we work with and alongside. We must also consider the effects of our research on our discipline and wider society. Reflecting on ethical dilemmas and weighing the positive and negative impacts of a project are essential to make informed decisions when planning a project and throughout a study. This can include the decision not to conduct a particular study, or to terminate it earlier than planned. In this chapter, I cover legal requirements and permits, then address the ethics of working with primates in captivity and the wild, specimen collection and working human participants. I then outline our ethical responsibilities to the natural environment, the people we work with, and the people we work alongside. I then highlight the importance of reflecting on our use of social media and the power of images, and end with our obligations to report and disseminate our findings.
We may already be convinced of the value of studying primates, but we often need to convince others of that value in proposals, reports and papers. This chapter covers the reasons to study primates, including appreciation of their fascinating diversity and adaptations, their important ecological functions, their evolutionary relationship with humans, their socio-cultural importance, concern for their captive welfare, and their conservation status.
Like all science, studying primates is about asking the right questions in the right way. Most studies of primates fall within the life sciences, so I focus on the scientific method in this book. This chapter introduces how science works, then what it takes to be a primatologist. I outline the contents of the rest of the book and highlight the importance of keeping science healthy. I end by emphasising the need to respect other people and to promote inclusive science.
In this chapter, we apply the affective social learning (ASL) concept to the social learning of natural skill sets in immature orang-utans since it can serve as an illustration of the majority of learning that occurs in wild apes. Most orang-utan social learning happens during everyday tasks and without any active involvement of the role model. Consequently, detecting the emotional state(s) of the role model is nearly impossible. We focus therefore on the emotional responses of the immature learners to the role models’ behaviours. Our data on peering (attentive, sustained close-range watching of conspecifics), which is often followed by selective practice of the observed behaviour by the peerer, suggests that there is some highly specific emotional arousal of the immatures during social learning. The role models’ actions with the object seem to play a central role in the learning process. However, immatures appear to decide on their own whether to attend to the information or not, as in affective observation, the second stage of ASL. Developmental changes in role-model preferences support the notion that trust in the role model is critical for ASL to work. Given that we can use the learners’ responses as proof of the affective states of the role models, ASL may be an important part of the mechanism that guides and optimizes the acquisition of learned skills in wild great apes. However, the lower we set the bar for the affective states (or emotions) of the role models for ASL to work, the more difficult it is to verify their presence and the more ASL will overlap with ordinary social learning.
Emotions have often been considered negatively in the animal literature, offering so-called parsimonious explanations to uncontrolled animal behaviour. This has particularly been the case for primate vocalizations, as opposed to flexible human language and potential goal-directed primate gestures. We believe that affective social learning (ASL) can offer a useful way to analyse emotions through a different perspective, integrating emotions and learning to analyse primates’ and other animals’ behaviour. In this chapter, we review the primate literature for potential cases of ASL, re-analysing classic cases such as the vervet alarm call system as well as more recent discoveries related to emotional behaviour. To decipher whether ASL is cognitively possible for non-human primates, we dissect the cognitive requirements for each step of ASL: emotional contagion, affective observation, social referencing and natural pedagogy. Our review suggests that, despite the lack of evidence for the latter step, there is evidence for all other types of ASL in primates, particularly in the domains of the ontogeny of communicative and cultural learning. We conclude by highlighting that ASL may constitute a useful comparative framework to describe various types of teaching that do not necessitate the demanding requirement of full-blown human intentional teaching.
In primates and carnivores, the main laminae of the dorsal lateral geniculate nucleus (LGN) receive monocular excitatory input in an eye-alternating fashion. There is also evidence that nondominant eye stimulation can reduce responses to dominant eye stimulation and that a subset of LGN cells in the koniocellular (K) layers receives convergent binocular excitatory input from both eyes. What is not known is how the two eye inputs summate in the K layers of LGN. Here, we aimed to answer this question by making extracellular array electrode recordings targeted to K layers in the marmoset (Callithrix jacchus) LGN, as visual stimuli (flashed 200 ms temporal square-wave pulses or drifting gratings) were presented to each eye independently or to both eyes simultaneously. We found that when the flashed stimulus was presented to both eyes, compared to the dominant eye, the peak firing rate of most cells (61%, 14/23) was reduced. The remainder showed response facilitation (17%) or partial summation (22%). A greater degree of facilitation was seen when the total number of spikes across the stimulus time window (200 ms) rather than peak firing rates was measured. A similar pattern of results was seen for contrast-varying gratings and for small numbers of parvocellular (n = 12) and magnocellular (n = 3) cells recorded. Our findings show that binocular summation in the marmoset LGN is weak and predominantly sublinear in nature.
Entamoeba histolytica is an enteric parasite that infects approximately 50 million people worldwide. Although E. histolytica is a zoonotic parasite that has the potential to infect nonhuman primates, such transmission is poorly understood. Consequently, this study examined whether E. histolytica is present among humans, chimpanzees and baboons living in the Greater Gombe Ecosystem (GGE), Tanzania. The primary aims were to determine patterns of E. histolytica infection in a system with human-nonhuman primate overlap and to test associations between infection status and potential risk factors of disease. Entamoeba spp. occurred in 60.3% of human, 65.6% of chimpanzee and 88.6% of baboon samples. Entamoeba histolytica occurred in 12.1% of human, 34.1% of chimpanzee and 10.9% of baboon samples. Human E. histolytica infection was associated with gastrointestinal symptoms. This was the first study to confirm the presence of E. histolytica in the GGE. The high sample prevalence of E. histolytica in three sympatric primates suggests that zoonotic transmission is possible and stresses the need for further phylogenetic studies. Interventions targeting better sanitation and hygiene practices for humans living in the GGE can help prevent E. histolytica infection in humans, while also protecting the endangered chimpanzees and other primates in this region.
Twenty-seven species and two subspecies of Ficus are reported from one study site in central Africa. Characters for identification are explained. An identification key, illustrations, descriptions and habitats are provided. The species-level diversity of Ficus in tropical forests is discussed.
There are several primate species with high risk of extinction in small forest fragments disturbed by human activities. However, some species exhibit high ecological plasticity, which allows them to persist in human-modified landscapes. The main goal of this study is to examine the relative roles of vegetation (mean distance among trees and mean canopy cover), human disturbance (distance to the road, distance to the fragment edge and edge type), and habitat spatial configuration (spatial autocorrelation index, category of quadrat – position within the fragment/fragment type) on the habitat selection of the black-tufted marmoset Callithrix penicillata in forest patches. We selected forest patches near and away from roads/urban areas, in southern Minas Gerais state, south-eastern Brazil. We used generalized linear mixed models to explain the presence of black-tufted marmoset in those patches. Our results show that black-tufted marmoset tend to occupy forest fragments closer to roads/urban areas, and consequently are under the influence of anthropic disturbance. In addition to the area delimited by these fragments, there is a preference for edge environments, where disturbances are exacerbated and the ecological conditions are suitable for exploitation by the black-tufted marmoset (supply of gum trees and reduced risk of competition). We suggest that a cross-habitat spillover by marmoset occur from forests to small habitat patches close to human-modified areas, such as those in proximity to roads and urban zones.
We present the first systematic assessment of the population, demography and distribution of the Endangered Zanzibar red colobus Piliocolobus kirkii, in Unguja in the Zanzibar archipelago, based on a survey effort of 4,725 hours. We estimate the total population comprises 5,862 individuals in 342 groups (mean group size 17.12); 3.4 times the mean of all previous estimates. We calculated a total area of occupancy of 376 km2, with 4,042 individuals living within protected areas. Mean group sizes were significantly higher within protected areas (20.57) than outside (12.80). The number of adult females was 3,179 (54.21%), with a mean of 9.29 per group, and the number of adult males was 932 (15.89%), with a mean of 2.71 per group, giving a ratio of 3.31 adult females to adult males. This ratio was significantly lower outside protected areas. The total number of infants was 958 (16.34%), with a mean of 2.80 per group, and the number of subadults/juveniles was 793 (13.52%), with a mean of 2.32 per group, giving ratios of 0.30 infants to adult females, and 0.25 subadults/juveniles to adult females. The results indicate that P. kirkii is resilient and thriving far better than assumed. However, recruitment is low and the population may be in decline, with individuals outside protected areas most at risk. We tentatively support the categorization of P. kirkii as Endangered on the IUCN Red List, argue for greater protected area status for southern Uzi, Vundwe and Mchamgamle, and discuss conservation implications for this charismatic flagship species.
The hepatitis E virus (HEV) has been described in humans and various animal species in different regions of the world. However, the knowledge on natural HEV infection in non-human primates and the corresponding risk of zoonotic transmission is scarce. To determine whether primates in captivity are affected by HEV infection, we investigated 259 individual sera of clinically healthy non-human primates of 14 species from nine German zoos. Using a commercial double-antigen-sandwich ELISA and a commercial IgG ELISA, 10 animals (3·9%) reacted positive in at least one assay. Three ape species and one Old World monkey species were among the seropositive animals: bonobo (Pan paniscus), gorilla (Gorilla gorilla gorilla), lar gibbon (Hylobates lar) and drill (Mandrillus leucophaeus). Testing for anti-HEV-IgM antibodies by commercial ELISA and for viral RNA by reverse-transcription real-time polymerase chain reaction resulted in negative results for all animals indicating the absence of acute HEV infections. In the past, no clinical signs of hepatitis were recorded for the seropositive animals. The results suggest that non-human primates in zoos can get naturally and subclinically infected with HEV or related hepeviruses. Future studies should evaluate potential sources and transmission routes of these infections and their impact on human health.
Sperm morphometry can be applied to identify different animal groups and species and to evaluate sperm quality. Furthermore, knowledge on species-specific differences will help to enhance biological information, as well as to develop efficient reproductive technologies. The aims in the present study were to describe sperm morphometry from the recently characterized species S. collinsi and S. vanzolinii, to verify if the morphometric sperm patterns are similar or different between both species, and to determine if the sperm morphometry is affected by the levels of sperm defects using the S. collinsi as a model. Semen was collected from S. collinsi (n = 10) and S. vanzolinii (n = 2) monkeys, and sperm was submitted to morphological analysis. From the 10 samples from S. collinsi, five presented sperm of poor quality and two subgroups were formed for this species, i.e. high and poor quality sperm. Data on sperm motility and vigour were analysed, as well morphometric parameters on sperm head and tail. It was observed the normal morphometry was correlated with high quality sperm. Poor quality sperm presented smaller and 7% more ellipticity in their head, when compared with high quality sperm. Sperm from S. vanzolinii presented larger head than those from S. collinsi, but tail lengths were similar. Sperm morphometry can be used as a complementary tool to predict sperm motility and vigour for the S. collinsi species, and S. collinsi appear as a suitable model for S. vanzolinii.
The primate malaria Plasmodium knowlesi has a long-standing history as an experimental malaria model. Studies using this model parasite in combination with its various natural and experimental non-human primate hosts have led to important advances in vaccine development and in our understanding of malaria invasion, immunology and parasite–host interactions. The adaptation to long-term in vitro continuous blood stage culture in rhesus monkey, Macaca fascicularis and human red blood cells, as well as the development of various transfection methodologies has resulted in a highly versatile experimental malaria model, further increasing the potential of what was already a very powerful model. The growing evidence that P. knowlesi is an important human zoonosis in South-East Asia has added relevance to former and future studies of this parasite species.
The study of malaria in the laboratory relies on either the in vitro culture of human parasites, or the use of non-human malaria parasites in laboratory animals. In this review, we address the use of non-human primate malaria parasite species (NHPMPs) in laboratory research. We describe the features of the most commonly used NHPMPs, review their contribution to our understanding of malaria to date, and discuss their potential contribution to future studies.
The presence of general intelligence poses a major evolutionary puzzle, which has led to increased interest in its presence in nonhuman animals. The aim of this review is to critically evaluate this question and to explore the implications for current theories about the evolution of cognition. We first review domain-general and domain-specific accounts of human cognition in order to situate attempts to identify general intelligence in nonhuman animals. Recent studies are consistent with the presence of general intelligence in mammals (rodents and primates). However, the interpretation of a psychometric g factor as general intelligence needs to be validated, in particular in primates, and we propose a range of such tests. We then evaluate the implications of general intelligence in nonhuman animals for current theories about its evolution and find support for the cultural intelligence approach, which stresses the critical importance of social inputs during the ontogenetic construction of survival-relevant skills. The presence of general intelligence in nonhumans implies that modular abilities can arise in two ways, primarily through automatic development with fixed content and secondarily through learning and automatization with more variable content. The currently best-supported model, for humans and nonhuman vertebrates alike, thus construes the mind as a mix of skills based on primary and secondary modules. The relative importance of these two components is expected to vary widely among species, and we formulate tests to quantify their strength.
Species showing mast seeding synchronously produce large amounts of fruits during some scattered years. This massive crop has been hypothesized to improve dispersal effectiveness by a satiation of seed predators, but the consequences for seed dispersers have barely been studied in the tropics. We tested the hypothesis that masting resulted in satiation of frugivorous dispersers using the study case of two Manilkara species growing in an Amazonian forest in French Guiana. Seed dispersal was estimated by means of seed traps in two forest types during a 10-y monitoring. Manilkara huberi and M. bidentata showed three fruiting events in a time span of 10 y (in 2001, 2006 and 2010). Estimates of seed dispersal from 2001 and 2010 showed that satiation of frugivores only occurred in the year with the largest crop of Manilkara (2010) and in the habitat where the diversity of primate-dispersed species retrieved in seed traps was the highest (Grand Plateau, with clay soils), while fruit consumers did not seem to be satiated in other instances. Spatio-temporal variability of seed production and the community-crop context are therefore affecting satiation of frugivores during masting events.