As human populations expand and modify landscapes, interactions between wild primates and domesticated animals have become increasingly frequent. This review synthesizes literature on primate-domestic animal interactions to assess patterns across these associations and set the context for the subsequent articles in the special issue on this topic. In our review, we sampled reports of directly observed interactions published in full-length manuscripts within the last 25 years. Dogs (Canis lupus familiaris) are the most frequently reported domestic species involved in agonistic encounters with primates, often acting as predators or human-directed deterrents in agricultural settings. In a sample of 100 search results for relevant key words, most interactions that were documented involved dogs (92% of 117 interactions recorded in 15 of 16 articles), most of which were free-ranging. Habitat type (agroforest, protected area, or town) showed an association dog type (free-ranging or with a known owner), where dogs with known owners in agroforest make up the largest proportion of interactions, followed by free-ranging dogs in agroforest. The nature of interactions (agonism or neutral) associated with taxonomic group, where no strepsirrhines were involved in neutral interactions with dogs, and all interactions with cattle were neutral. Despite the impact of domestic animals on wild primate populations, systematic studies on primates and domestic animals, especially beyond canines, are often limited. To better understand the nature of anthropogenically influenced interspecies interactions, we recommend that researchers distinguish between the degree of human control domesticated animals are under, document the behavioural responses of both primates and domestic animals, and include interactions with non-canine domestic species, such as livestock.

The Southern Lesser Bushbaby Galago moholi is a small, nocturnal, strepsirrhine primate, native to Sub-Saharan Africa. Previously considered a strict dietary specialist on tree exudates and insects, recent observations have revealed hitherto unappreciated plasticity in its feeding behaviour, encompassing fruits and even small vertebrates. While arthropods are an important seasonal component of the diet of this species, we still have little idea of the types of insect prey taken in nature, or the extent of any preferences among arthropod taxa. Here, I document behavioural observations made of G. moholi foraging at a moth trapping light on two occasions in November 2024 in Limpopo (Republic of South Africa), including details of feeding preferences and previously undocumented foraging vocalisations. To understand species-level preferences among potential insect prey, I presented an individual G. moholi with various prey types and recorded which were consumed. In addition, using male Driver Ants Dorylus helvolus, I experimentally manipulated prey items to gauge the relative importance of prey appearance, movement, and sound in determining their attractiveness to G. moholi. Lepidoptera were strongly favoured among available prey options, with increased discrimination applied to other groups such as Coleoptera and Hemiptera. Both sound and movement were important in determining predation from G. moholi. Although limited by low replication, these observations are the first to document species-level discrimination and preferences among a wide range of insect prey in wild G. moholi. Building a clearer picture of the dietary ecology of this species is vital for its conservation, and for better understanding its functional role in woodland food-webs. Future studies should seek to employ more systematic experimental approaches on captive and wild individuals (i) to clarify the traits that make different arthropod taxa suitable/attractive prey for this species, and (ii) to further explore the sensory ecology of G. moholi foraging, particularly the relative role of vision and audition.

Amongst the colobines (Colobinae subfamily), the douc langurs (Pygathrix) are known to use higher proportions of arm-swinging behavior in their locomotor repertoire. Previously, researchers have suggested the increased use of arm-swinging to be a result of habitat constraints. For example, suspensory locomotion allows animals to travel across unstable substrates, such as the terminal ends of branches, than would be possible in above branch locomotion. In this paper, we attempt to identify patterns of habitat use and arm-swinging amongst the doucs. Specifically, we predict arm-swinging will occur significantly more on horizontal substrates, in the main canopy, on branches (medium-sized substrates), and in old-growth forest. Data was recorded in the Son Tra Nature Reserve, Vietnam between November 2016 and April 2017. The monkeys were filmed and data was extracted continuously. Results indicate the red-shanked douc arm-swings more often when they are in the main part of the canopy compared to the top of the canopy, and possibly on substrates smaller than a bough. No differences were found in frequency of arm-swinging when individuals were in old versus new forest or on horizontal versus oblique substrates. The patterns of arm-swinging behavior follow patterns similar to that of spider monkeys, especially in substrate preferences. This information is critical for understanding and conserving the habitat of the critically-endangered red-shanked douc.

Many primate species consume insects as part of their regular diet, yet few researchers have systematically collected them and analyzed their nutritional content. In this study, we developed protocols for collecting and analyzing prey items consumed by Weddell's saddleback tamarins (Leontocebus weddelli), focusing on Orthoptera (crickets, grasshoppers, and katydids) which have been documented to be a central component of their diet. We used five methods to collect insect prey (pitfall, sheet, water, moth trap and manual capture) at a field site in northwestern Bolivia over the course of two months. In total, we collected 1302 insect samples, which we photographed, weighed, dried, and sorted into nine taxonomic groups (Acrididoidea/Eumastacoidea, Blattodea, Cicadoidea, Gryllidae, Lepidoptera, Mantodea, Phasmatodea Proscopiidae, and Tettigoniidae). We then analyzed the samples for their macro- and micro-nutrients. We found that the manual capture method was the most effective for capturing orthopterans. Our analyses showed that the samples primarily contained crude protein (52.63-78.54 % dry matter (PCDM)), chitin (12.05-27.26 PCDM) and fat (4.63-15.6 PCDM). The samples also contained high levels of a wide variety of minerals, including iron (42-655 parts per million (ppm)), zinc (85-554 ppm), and manganese (37-1200 ppm). These results indicate that orthopterans and other Neotropical insects can serve as important sources of macro- and micronutrients for tamarins. Given the variation in nutrient content among taxa, we recommend that researchers collect and analyze insects that most closely resemble the prey consumed by their study subjects to determine their nutritional value, and not assume equivalent nutritional composition across species, higher taxa, or life stages. Given the success of using night walks with manual capture for collecting Orthopterans, we recommend that other primatologists use this method to allow for cross-site comparisons of insect nutrition.

Howler monkeys are well-known for producing long calls ("roars") as a means of long-distance communication. The ecological resource defense hypothesis posits that animals roar to defend food resources; thus monkeys should modify roaring behavior across seasons and between sites with varying food resource abundance. We investigated mantled howler monkey roaring behavior between the wet and dry seasons at a large, continuous lowland wet forest (La Selva Research Station) in northeastern Costa Rica as well as between La Selva and a nearby small forest fragment (La Suerte Biological Research Station, LSBRS). We quantified a proxy of resource abundance at each site by measuring tree diameter at breast height (DBH) and canopy cover and used all-occurrences sampling to collect data on roaring behavior. We calculated number of roars per minute, length of roar bouts, and roar bouts per hour. Number of roars per minute was significantly higher at La Selva during the wet season than the dry season. With respect to comparisons across sites, both canopy cover and DBH were significantly higher at La Selva. Correspondingly, the length of roar bouts and the number of roars per minute were significantly higher at La Selva. Roar bouts per hour, however, were significantly higher at LSBRS, which may be explained by the very high population density at LSBRS. The results for our comparison demonstrate that some features of howler monkey roaring behavior vary along with ecological conditions and that other non-ecological factors may also drive elements of roaring.

Human presence and climate constraints shaped the primate adaptation to employ behavioural strategies. In this study, we examined the relationship between the food environment (human presence and microclimate) and behavioural responses of long-tailed macaques (Macaca fascicularis) in secondary and mangrove forests of coastal habitats on Belitung Island, Indonesia, over six months (March-August 2023), with 509 h of total observations. The macaques were mainly frugivorous, but a small amount of human food consumption persisted in response to the presence of humans. The macaques spent more time resting and autogrooming, decreased both moving and feeding, fed more on human food, reduced mature fruit consumption, and decreased home range sizes when visitors were more present. Furthermore, higher humidity levels decreased feeding activity and reduced the consumption of mature fruit, seed, other plant matters, and water intake in macaques, whereas the frequency of their autogrooming and canopy usage increased. Rainfall and temperature did not substantially exhibit relationship with behavioural ecology of macaques, which supported other long-tailed macaque responses from several regional sites. The macaques appeared to have adapted to human presence and microclimate by employing an energy-minimizing strategy, i.e., using the least costly energy in activity and ranging behaviour in taking human resources, and shifting activity, diet, and particular strata as microhabitat selection during humidity stress. Overall, macaques exhibited a generalist primate species where their behaviour and dietary adaptation allowed them to address anthropogenic and microclimate pressure. Our findings provided valuable reports and essential data for developing conservation programs and strategies, particularly concerning the impacts of human presence and climate change on macaque behaviour.

Domestic dogs (Canis familiaris) are an invasive species that can affect wildlife behaviour and contribute to species extinction. In Diani and Galu, southeastern Kenya, they injure or kill colobus monkeys (Colobus angolensis palliatus) more than the other monkey species in the area. This study investigated how arboreal colobus in these suburban areas adjust anti-predator strategies to a dog-dense environment. From May to July 2018, we conducted focal follows on two colobus groups (Group A: 103 h; Group B: 98.5 h) with home ranges overlapping with dogs and where previous dog-colobus attacks were witnessed. Dog-colobus interactions (⩽20 m from a dog) occurred in 2% of observation hours, with 70% of interactions involving dog predatory behaviours. The primary anti-predator behaviour was vigilance during the interactions and moving away rather than fleeing. When we mapped these interactions, the high-risk areas accounted for 12 and 13% of the total home ranges, respectively. Both groups spent about half their time foraging in these high-risk areas, did not stay high in the vegetation while there, and did not socialise or rest more frequently in the low-risk areas. A 1969 study of colobus vocalisations in the same area described colobus responding to dogs with vocalisations, threat displays, and fleeing - typical anti-predator behaviours of the genus. We conclude that over 55 years of exposure and habituation to dogs in a rapidly growing suburban environment have diminished anti-predator responses. Although frequently employed anti-predator behaviours would be energetically costly, reduced expression may ultimately increase colobus vulnerability to dog predation.

Nocturnal primates primarily rely on olfactory and acoustic cues for conspecific recognition and communication, but researchers have comparatively understudied the role of vision. Here, we investigated how visual cues function in the nocturnal aye-aye (Daubentonia madagascariensis) to address this gap. We used a Tobii Spectrum Pro eye tracker to measure attentiveness to visual stimuli in six captive aye-ayes (f: 5, m: 1) across two gaze-tracking paradigms. We employed generalized linear mixed models, including subject identity as a random effect, to assess the relationship between stimulus type and gaze metrics. In the Thatcher Illusion paradigm, subjects made more whole fixations when viewing non-Thatcherized images than Thatcherized ones. In the preferential-looking paradigm, subjects also demonstrated greater attentiveness to conspecifics compared to other species. However, subjects did not show significant differences in their attention among individual conspecifics. Our results demonstrate that aye-ayes use visual cues for conspecific recognition. These findings provide new insights into primate evolution, adaptations to the nocturnal niche, and the trade-offs between olfaction and vision.

Uncontrolled urban sprawl is leading to loss of ecosystems and the degradation of habitats for many species. This, along with wildlife trafficking is pushing primates to live closer to urban areas, resulting in conflicts between humans and animals. To promote peaceful coexistence, environmental education is crucial. In 2018, we launched an educational initiative aligned with Jane Goodall's Roots and Shoots Educational Program, founded by Jane Goodall and developed by Jane Goodall Institute worldwide. Nowadays, our environmental educational group's efforts aim to cover the ecological education aspect of the Ecuadorian Primate Conservation Action Plan. One of our key campaigns is the Misahuallí Capuchin Monkey Management Plan. Misahuallí is surrounded by Kichwa communities and is a hub for illegal trafficking. The city has been home to a group of capuchin monkeys since the late 1970s, becoming a town symbol and an important tourist attraction. However, the population has dwindled in recent years due to different pressures related to the urban environment, such as electric cables, road kills, conflicts with domestic animals, bad food provided, and sickness transmitted through direct interaction with humans. This context presents a unique opportunity to improve animal welfare, respect, illegal trafficking, and the correct human treatment of wildlife, specifically towards the capuchin monkeys' group. Our results show increased local awareness of these issues following the project. These findings highlight the importance of engaging a committed local team, establishing long-term educational programs to ensure conservation actions' sustainability, and local authorities' crucial role in allocating budgets to strengthen public policy frameworks.

Long-tailed macaques (Macaca fascicularis) show remarkable adaptability in their patterns of habitat-use. Some populations have adapted to ecological niches with a high magnitude of anthropogenic impact. Along with adjusting to the presence of humans, long-tailed macaques must also share space with a wide range of other species which humans have domesticated. These domesticates vary in their form and function in anthropogenic habitats, and therefore may interface with long-tailed macaques across a range of ecological and social contexts. In this paper we present observations of long-tailed macaques at the Padangtegal and Uluwatu temples in Bali, Indonesia interacting with domestic dogs, cats, and cattle. While anecdotal, these observations reveal a spectrum of interactions between long-tailed macaques and these domesticates, beyond simply bidirectional aggression. These observations may indicate that long-tailed macaques are able to read and respond to human domesticates within their shared physical and social environments, as they have been demonstrated to do with humans. Such a capacity would represent another dimension of the long-tailed macaque's adaptability.

Brazil, a country with a rich diversity of primates, faces the challenge of preserving these species, since most are at some level of threat of extinction. Among Brazilian primates, the pygmy marmosets (Cebuella niveiventris and C. pygmaea) stand out as the smallest known species of monkey, with a wide distribution in the western Amazon. Faced with the need for quick and well-founded information to guide conservation, recent studies have used analyses of Species Distribution Models (SDMs) for primates. The present study aimed to investigate the genetic diversity in Cebuella, using the mitochondrial gene cytochrome b, and analyze the potential distribution (SDMs) of the two species. The phylogeny showed Cebuella divided into two clades, corresponding to the two species of the genus, corroborating previous findings. Herein, we applied species delimitation tests to the genus Cebuella for the first time, revealing significant divergences. The bPTP method identified six probable species within Cebuella, while the ABGD indicated 15 putative species. Both methods point to a high diversity within the genus. Species suitability modeling suggested that C. niveiventris seems to be more sensitive to seasonal variations in rainfall (BIO15) and the amount of rainfall during the wettest quarter (BIO8), while C. pygmaea appears more impacted by the intensity of the early rainy season (BIO15) and a period of lower rainfall variability throughout the rest of the year. The most pessimistic scenario for the future suggested that the more intense the environmental changes resulting from human activities, the greater the impact on future climates, increasing the probability of population decline.

Nonhuman primates are threatened across their distribution, with habitat loss, disease, poaching, and the pet trade causing widespread population decline. An understudied threat is the growing presence of cattle in primate habitat, with the increased exposure to human and bovid pathogens, domestic dogs that accompany herders, and habitat degradation. We investigated cattle-primate spatial and temporal overlap using 13 motion triggered cameras over a 16-month period (2023-2024). We detected cattle and primate presence in 5/13 cameras, all in open vegetation (woodland or grasslands). Yellow baboons and vervet monkeys spatially overlapped with cattle, whilst chimpanzees and red-tailed monkeys were only observed in riparian forests, and so did not overlap with cattle. We found no relationship between primates and cattle observations ( r 2 = 0.49, n = 12, p = 0.1), suggesting that there is no avoidance between species but we did find an effect of season on primate activity on cattle-present vs cattle-absent cameras ( χ 2 (1, N = 176) = 7.21, p = 0.007), with more primate observations on cattle-present cameras during the dry season. Primates and cattle observed on the same cameras exhibited similar diel activity patterns, compared to earlier and later primate presence in non-cattle cameras. We conclude by discussing the implications for cattle-primate overlap, and next steps to better understand this coexistence.

Characterizing activity budgets in response to seasonality and anthropogenic pressures provides insights into primate behavioral ecology. The Arsi geladas (T. gelada arsi) are a distinct and little-known subspecies of geladas living south of the Rift Valley in eastern Arsi, Ethiopia, where elevation and rainfall levels are low, temperatures are high, and habitat loss and degradation threaten the geladas. To better understand how Arsi geladas cope with the challenges of their highly disturbed and climatically challenging environment, we conducted 16 months of observational scan sampling on a focal band of approx. 35 individuals (consisting of two one-male units) at Goro-Jena to examine diurnal and seasonal variation in their activity budgets. Overall, Arsi geladas spent most of their time feeding (57.3 ± 5.0%), followed by socializing (18.7% ± 3.8), moving (12.5 ± 5.0), and resting (10.2 ± 3.1). Feeding peaked in the late morning and late afternoon and social behavior peaked in the early morning near sleeping sites. Resting also peaked in the early morning as well as around mid-day, when ambient temperatures were warmest, the latter peak potentially reflecting the thermoregulatory challenges of the hot climate in Arsi. Arsi geladas exhibited only minor seasonal shifts in their activity patterns with increases in feeding time corresponding with periods of lower resource availability and quality. Percentage of time devoted to feeding by geladas at Goro-Jena was comparable to that of some populations at high elevations which themselves must cope with cold climates. This finding suggests that Arsi geladas at Goro-Jena occupy a marginal environment that imposes substantial energetic stress on them. As such, priority conservation actions must include protecting and expanding natural gelada habitat at Goro-Jena - as well as elsewhere in Arsi - to ensure the persistence of this increasingly rare and threatened gelada subspecies.

Introduced species, also known as invasive species, alien species and exotic species, are a major contributing factor to environmental problems in that they modify or disrupt the ecosystem they colonize. While some invasive species arrive in new areas through natural migration, more often than not they are introduced by the activities of humans. For example, domestic cats (Felis catus) were introduced by humans and are now common pets. Cats have been so successful invading new areas that their worldwide population is reported to exceed 500 million. Over 3 decades of u observations, cats were observed 169 times while observing Gursky's tarsier. Over time, the frequency that cats were observed while observing tarsiers increased. Similarly, the distance from the village that cats were observed increased over time indicating that the cats are moving further into the protected area. The tarsiers exhibited numerous responses to the presence of a cat. They always alarm called, and occasionally mobbed the cat. Several behavioral changes were made including increasing time traveling, increasing their height in the forest canopy, decreasing distance between group members. The cats attempted to prey on a tarsier 19 times. Twelve attempts were successful. Given that cat predation is known to have already caused faunal extinctions on islands, this threat to the tarsiers and other endemic species in Tangkoko Nature Reserve should not be taken lightly. One potential way to mitigate the negative impacts of cats on the tarsier population is by developing bylaws that restrict cat ownership adjacent to protected areas.

People play an important role in the welfare of nonhuman animals in zoos. The aim of this study is to find out if the behavior of squirrel monkeys maintained in Faunia, a zoological and botanical garden located in Madrid (Spain), and the height they occupy in their enclosure is associated with the flow of visitors and the keeper presence. Although the effects of visitors and keepers were difficult to separate, the response to increasing flow of visitors was not linear, being usually associated with greater individual variability in responses. In a more precise way, when the flow of visitors increased, feeding and locomotion decreased, while resting and interactions with people increased. Although decreasing of positive behaviors as feeding seems to indicate that monkeys perceive high numbers of visitors as a nuisance, interactions with people suggest that those could consider visitors as a kind of environmental enrichment.

We studied an adult female and a juvenile male aye-aye (Daubentonia madagascariensis) in Madagascar's Ihofa forest from May to December 2017 to investigate whether the postural diversity of this lemur varied with age, maintenance activity, and habitat use. We used bout sampling (female N = 488, male N = 355) to record postures during feeding and resting and tested for differences using χ 2 . For both individuals, bimanual and unimanual cling were the most common postures used during feeding (78.4% and 82.9%) and these behaviors were strongly associated with the use of vertical supports - trunks and bamboo - in the main canopy. When feeding on branches and boughs, pronograde postures such as tri-pedal crouch and crouch were most common. Most rest occurred on horizontal branches using primarily pronograde postures. Our data indicate that although aye-ayes exploit multiple forest strata, the great majority of feeding is accomplished using orthograde postures from vertical supports, even in forest strata dominated by horizontal supports. These findings support recent arguments about the significance of vertically oriented behaviors in the evolution of early mammalian arboreal quadrupeds.

We explore the impact of teaching methods and learning styles on student engagement in a conservation education program focused on primate conservation in Indonesia. Engaging students is essential for fostering environmental literacy and encouraging pro-environmental behaviours. We assessed the effectiveness of active versus didactic teaching methods and visual, auditory, and kinaesthetic learning styles in enhancing engagement. Using a formative assessment approach, we observed student participation and attentiveness across 19 different activities in a Nature Club program. Our results indicated that active teaching methods significantly increased engagement, while auditory learning styles were associated with lower levels of engagement. The findings emphasise the importance of adopting active learning strategies and tailoring activities to accommodate diverse learning styles to maximise student involvement. This research contributes valuable insights into the design of conservation education programs that effectively promote long-term environmental stewardship among young learners. Furthermore, this method can easily be adapted to evaluate a range of different conservation education programmes.

Marmosets are obligate gummivores with evolutionary adaptations to harvesting tree exudates. We studied a group of zoo-living free-ranging silvery marmosets (Mico argentatus) that had learned to feed from Prunus spp., to investigate the characteristics of the holes they gouged in four Portuguese laurel trees (Prunus lusitanica). Holes were frequently extended in more than one direction from the base, often producing roughly V-shaped channels. The angles of the holes from the vertical were significantly different from a random distribution and averaged 40° ± 2.1 SE. Mean hole length was 50.9 mm ± 3.4 SE. Mean depth of gouge holes was 5.08 mm ± 0.17 SE and was consistent along the length of the holes. Feeding on Prunus was concentrated in the late morning, and constituted 26.2% of records of the marmosets' overall activity during group scans. Further studies are needed to investigate whether there are consistent species or generic differences in the methods used to harvest gum by marmosets, and whether marmosets use different gouging techniques for different plant species. Understanding how marmosets identify and use new gum sources will be important for their conservation in habitats altered by anthropogenic impacts.

Lemurs are the most endangered group of mammals on earth, and invasive species, including domestic dogs, are considered to be the second greatest threat to biodiversity after habitat loss. Here, we describe and summarize the challenges and results of a decade of research aimed at understanding the impact of dogs on lemurs, and efforts to humanely reduce dog populations in protected areas in Madagascar, to reduce their impact on lemurs and other wildlife, via the non-profit the Mad Dog Initiative. We have found that free-roaming domestic dog populations living in and around Madagascar's protected areas both predate and displace native wildlife, and that the presence of dogs in forests drives a reduction of wildlife in forests. Additionally, dogs vector a number of pathogens that can have lethal consequences for lemur populations, as well as serving as important vectors of anti-microbial resistance. We propose several future directions for research, outreach, and capacity building in Madagascar and other low and middle income countries aimed at better quantifying the threat of domestic species on wildlife, and mitigating its impact.

Kibale National Park (KNP) is a biodiversity hotspot. Covering 795 km2 it is home to the most diverse population of primates in Africa including 13 species and the largest populations of Eastern Chimpanzees (Pan troglodytes schweinfurthii) in East Africa. Rural communities around the park rely heavily on subsistence agriculture and natural resources that surround the park for survival. Population density near the park is greater than 300 people per kilometer, exacerbating pressure on natural resources around and within the park. UNITE for the Environment (UNITE) is a conservation organization working with KNP that provides communities with conservation education programs that address local environmental needs and promotes sustainable solutions to support the protection of this important primate habitat. In prior work, UNITE found considerable variation in how well these sustainable activities are adopted. To understand the factors that influence uptake of different sustainable practices by households, we conducted a community survey on participants' motivations and barriers. Results highlight a number of factors influencing adoption including education and awareness, access, convenience, economic and direct benefits associated with the practices as well as community influence. These results imply that efforts to promote the widespread adoption of sustainable practices should focus on creating more awareness on sustainable behaviors in the targeted communities, which can change their perceptions and attitudes towards the practices and emphasize the direct benefits that arise from adoption of such practices.