International Journal of Primatology最新文献

Mammalian mothers flexibly invest in their offspring to maximize their lifetime fitness. Flexible maternal investment may be particularly important in large-brained species with prolonged maternal care, e.g., in great apes. We investigated the effects of socioecological factors and mother–offspring characteristics on nine maternal behaviors in wild Sumatran orangutans (Pongo abelii; N = 22 mother-offspring pairs; >11,200 hr of focal data from 2007–2022) using generalized linear mixed models. The behaviors fall under four maternal functions: locomotory support (carrying), skill acquisition support (feeding in proximity, food transfer), protective proximity maintenance (body contact and proximity initiation, following), and independence promotion (body contact and proximity termination, avoiding). Mother’s parity was not significantly associated with any maternal behavior. Mothers were more likely to show locomotory support, skill acquisition support, and protective proximity maintenance toward younger than older offspring, whereas they were more likely to promote independence in older than younger offspring. Mothers with male offspring were more likely to show skill acquisition support to their offspring than those with female offspring. With increasing food availability, skill acquisition support reduced. With increasing association size (i.e., the number of individuals within 50 m of each other), mothers were more likely to show protective proximity maintenance and less likely to promote independence. When males were present, mothers were more likely to show locomotory support to their offspring. Sumatran orangutan mothers thus flexibly adjust offspring-directed behavior in response to prevailing socioecological factors and mother–offspring characteristics. Our findings add support to the evolutionary theory that mammalian mothers flexibly invest in their offspring.

Females other than the mother often handle infant primates. In some cases, this infant handling can affect the infant negatively and persist after that (excessive infant handling [EIH]). We tested two hypothesized functions (reproductive competition and social bridging) and three hypothesized mechanisms (social exchange, inexperience, and accessibility) for EIH to investigate why and how handlers perform EIH. We recorded infant handling bouts (n = 1446) involving 12 wild, 0- to 16-week-old Japanese macaques inhabiting Yakushima Island (Macaca fuscata yakui) through all-occurrence sampling. We found that aggression tended not to become EIH and that adults performed EIH more than subadults and juveniles. We also found that handlers groomed mothers less before EIH than before non-EIH. Handlers performed EIH, rather than non-EIH, toward infants who were out of contact with mothers and those of closer-ranking, higher-ranking, and unfamiliar females. These results suggest that EIH is not performed for reproductive competition but for social bridging with higher-value social partners. Social bridges with such individuals may be important in despotic species, such as that of the Japanese macaque. Our findings also suggest that EIH does not occur through proximate mechanisms of social exchange and inexperience with infants but partially through accessibility of infants. Handlers reduce the cost of EIH by choosing accessible infants (those who were out of contact with mothers and those of closer-ranking females), but at the same time, maternal tolerance allows the handlers to choose inaccessible infants (those of higher-ranking and unfamiliar females). Our study provides clear evidence of social tolerance in a despotic system and insights into natal attraction that negatively affects infants in wild primates.

The global trade in nonhuman primates represents a substantial threat to ecosystem health, human health, and primate conservation worldwide. Most of the primate trade involves trade for pet-keeping, consumption, or biomedical experimentation. We present an overview of international primate trade through five case studies; each describes a different facet of this trade. We draw on published scientific literature, media outlets, and open access datasets, including the CITES Trade Database to build these case studies. Case study 1 describes the role of introduced island populations of Macaca and Chlorocebus in trade for biomedical experimentation; case study 2 covers the global health threats posed by the primate trade, including zoonotic disease transmission once animals enter the trade pipeline; case study 3 addresses the ways that changing patterns of primate trade, from local markets to online, have increased the demand for primates as pets; case study 4 recognizes the role that local environmental activism can play in mitigating trade; and case study 5 shows variation between global regions in their contribution to the primate trade. We recommend greater oversight of primate trade, especially domestic trade within primate range countries, and real-time reporting to CITES to accurately track primate trade. Effective conservation-focused regulations that can minimise the negative effects of primate trade must be tailored to specific regions and species and require transparency, careful regulation, field research, and an understanding of the magnitude of this trade.

Studies integrating patterns of molar morphology and diet are particularly useful to address questions of evolutionary history and diet in extinct taxa. However, such studies are lacking among lorisoids compared with other primates. Lorisoidea is distinctive when considering diet as some taxa consume large quantities of gums or exudates, whereas others consume none. Although there has been previous study of the relationship between craniodental form and exudate feeding, little is known about how patterns of exudate feeding covary with variation in molar topography. We analyzed a sample (n = 52) of lorisoids representing 17 extant taxa and one extinct taxon (Karanisia clarki). We used dental topographic metrics to quantify functional aspects (i.e., curvature, complexity, and relief) of occlusal morphology. We also used ancestral state reconstruction to estimate topographic parameters for the last common ancestors (LCA) of Lorisoidea, Lorisidae, and Galagidae. As with previous studies, we found that higher topographic values characterize insectivores, whereas frugivores tend to have lower values. We reconstructed the LCA of Lorisoidea, Lorisidae, and Galagidae as insectivorous, with Lorisidae slightly more insectivorous, and potentially more exudativorous than Galagidae. Moreover, we identified a significant interaction between the primary dietary component (i.e., fruit or insects) and the level of exudate feeding in our sample, with exudate-feeding insectivores being associated with lower topographic values than exclusive insectivores. Finally, we reconstruct K. clarki as an insectivore, contrary to previous findings, although whether the animal fed on exudates remains ambiguous. Overall, our results provide a framework for testing ecological hypotheses about lorisoids and may point to a unique pattern of molar topography among exudativores.

An accurate representation of species diversity is critical in primatology; most of the questions in evolutionary biology, ecology, and conservation hinge on species as a fundamental unit of analysis. Galagos are among the least-known primates. Because of their cryptic morphology, broad distribution, and sampling challenges arising from elusive habits and political instability, substantial knowledge gaps about their taxonomy, evolutionary history, and biogeography remain. Despite these limitations, recent research that integrated field surveys, acoustic, morphological, and genetic analyses helped us to better understand the taxonomic diversity of this primate group. In this paper, we (1) review the current status of galagid taxonomy; (2) synthesize our current understanding of their phylogenetics, origins, and biogeography; and (3) explore current and future approaches to elucidate galagid cryptic species diversity. The onset of galago systematics dates back to the early 19^th century, with taxonomic descriptions following natural history expeditions and comparative anatomy studies. Although morphology has historically dominated systematic research on galagos, the coupling of acoustic analyses with genetic data has revolutionized the field. Taxonomic rearrangements include the discovery of new species in the wild (e.g., Galagoides kumbirensis) and the description of a new genus (Paragalago). Technological advances have allowed the collection of acoustic data in remote areas, and molecular techniques have the potential to help researchers fill important geographic gaps. Improving the resolution of galago species diversity also has implications for the conservation of wild populations, as a better understanding of species boundaries and ranges can aid in the implementation of conservation strategies.

Temperate living primates cope with a variety of environmental stressors, which may vary by body mass. We studied two sympatric galagos, the thick-tailed greater galago, Otolemur crassicaudatus (1.5 kg) and the southern lesser galago, Galago moholi (146 g), living in a South African northern mistbelt forest. We used 75 nightly encounter walks using thermal imaging from July 2017 to June 2018 to locate galagos (245 thick-tailed greater galago encounters, 207 southern lesser galago encounters). For each species’ encounters we documented survey location, growing season, insect and gum availability, ambient temperature, temperature season, rainfall, humidity, night length, hour, moon phase and fraction of moon illumination. We encountered the southern lesser galago at both cooler and warmer temperatures, later in the night, and more often during greater lunar illumination, e.g., they were lunarphilic. We had few encounters of the thick-tailed greater galago during very cold and very warm temperatures, more encounters earlier in the night, and more encounters during periods of low lunar illumination, e.g., they were lunarphobic. Our results can be understood in terms of body mass differences. A smaller body mass requires greater and more consistent energy, meaning the southern lesser galago needs to both maintain energy needs across different temperature regimes and to forage more extensively later in the night to attain enough food to support them throughout the following day. The thick-tailed greater galago’s larger body mass may buffer them during colder periods and allow them to forage earlier in the night. Being either lunarphobic or lunarphilic may relate to activity patterns of their predators. The southern lesser galago are visually oriented insect predators and being lunarphilic may facilitate both predator detection and enhance successful insect predation. Understanding how body mass may facilitate or hinder physiological and behavioral responses to environmental stressors is thus relevant to understanding species’ resilience to climate change.

The expansion of shared spaces between humans and wildlife, particularly resulting from agricultural encroachment on natural habitats, leads to increasing interactions between humans and non-human primates (hereafter “primates”). We explored how crop-foraging Barbary macaques adapt their behavior to anthropogenic disturbances and identified deterrents implemented by farmers and their effectiveness. We observed three groups of crop-foraging Barbary macaques in Aïn Leuh, Morocco, in 2021–2022. We estimated their activity budgets from 7185 scan records and tested whether they were influenced by habitat (forest, fruit orchard, and cereal field). Additionally, we examined the impact of time of day, month, and age-sex class (adult female, adult male, immature) on macaque presence in cultivated areas. We also analyzed macaque responses to encounters with humans and dogs. Macaques primarily focused on feeding in cultivated areas while allocating more time to resting and socializing in forested areas. They used cultivated areas extensively during periods of human activity. Cereal fields, but not orchards, were predominantly visited by adult females rather than males or immatures. Macaques experienced 0.34 to 0.67 anthropogenic encounters per hour, with variation across months, and high rates of aggression from humans and dogs. Preemptive deterrence measures, such as using slingshots before macaques entered the crops, were more effective than confrontations inside the cultivated areas. While crop-guarding with slingshots was effective, it poses risks to the macaques. This study highlights the high risk of crop-foraging for Endangered Barbary macaques and the need to develop safer and more sustainable crop-guarding strategies to mitigate conflicts and promote human-Barbary macaque cohabitation.

Epidemics have significant impacts on primate populations. In 2016, yellow fever spread rapidly to the most densely populated states of Brazil, resulting in the death of hundreds of humans and thousands of nonhuman primates. The Yellow Fever Surveillance Program (Programa de Vigilância da Febre Amarela) implemented by the Brazilian government was designed to prevent and control yellow fever outbreaks. In 2020, the regional reference laboratory at the Oswaldo Cruz Institute in Rio de Janeiro state in Brazil, responsible for yellow fever diagnosis, gave us access to 24 DNA samples from capuchin monkeys, which had tested negative for yellow fever virus. The samples were all from sites in Brazil where Sapajus nigritus is the only species of capuchin monkey present. We attempted to sequence two mitochondrial molecular markers commonly used for Cebidae, but five samples did not amplify. In this study, we performed additional DNA amplification and the Basic Local Alignment Search Tool (BLAST) to confirm the species identity of the 19 samples, which amplified and identify the taxon of the five samples that had failed to amplify. Among the 19 samples correctly identified as Sapajus, one was not Sapajus nigritus but another Sapajus species. Of the five samples that previously failed to amplify, three were similar to Callicebus nigrifrons, one was similar to Alouatta guariba clamitans, and one failed to amplify successfully for any marker. These findings show an error rate of 5/24 (21%) in the original taxonomic identification. Misidentification occurred at the genus level as well as the species level. Our findings highlight the importance of precise taxonomic classification in obtaining reliable data on the consequences of the yellow fever epidemic for primates.