Human evaluation of animal emotional expressivity can inform animal welfare. Qualitative Behavioural Assessment (QBA) has been applied to domesticated and some non-domesticated animals, but its use in primates is limited despite their emotional expressivity. We aimed to develop and apply a QBA for bonobos (Pan paniscus) through two consecutive studies. We applied Free Choice Profiling (FCP) and the Fixed List methodology, respectively, in Study 1 and 2, and invited students and bonobo experts to rate video clips of zoo-living bonobos of different sexes and age classes, and before and after moving to a new enclosure. In Study 1, students described dimension 1 as ranging from ‘quiet/calm’ to ‘angry/active’ and dimension 2 from ‘sad/anxious’ to ‘happy/loving’. Experts described dimension 1 ranging from ‘quiet/relaxed’ to ‘nervous/alert’ and dimension 2 from ‘nervous/bored’ to ‘playful/happy’. Using a fixed list of descriptors, informed by findings from Study 1, students in Study 2 described dimension 1 as ranging from ‘quiet/calm’ to ‘agitated/frustrated’, and dimension 2 from ‘sad/stressed’ to ‘happy/positively engaged’. Experts described dimension 1 as ranging from ‘quiet/calm’ to ‘active/excited’, and dimension 2 from ‘sad/bored’ to ‘happy/positively engaged’. Students scored adults as more ‘calm/quiet’ and experts scored subadults as more ‘happy/positively engaged’. Additionally, experts in Study 2 rated bonobos as more ‘active/excited’ in their new enclosure. Reliability was moderate to good for the dimensions. Additionally, animal-directed empathy of observers influenced QBA scores. This is the first time, FCP has been successfully used as a method to study primate emotional expressivity. Our findings show the promise of employing QBA in primate studies and in industry, with validation of additional metrics to enable its use for welfare-monitoring purposes.

Unsustainable hunting threatens biodiversity in the tropics through the removal of key seed-dispersing frugivorous primates. Traditionally, hunting in the Amazon Basin was managed through hunter territoriality, with the threat of social sanctions for overexploitation. We examined hunter territoriality and differential prey selection as alternative hypotheses to central-place foraging. Territoriality occurred beyond common hunting grounds, which were on major rivers and immediately surrounding the community. Hunters displayed selectivity in prey choice, with 50% of hunters not hunting primates. The combination of hunter territoriality and differential prey selection means that over 22% of the hunted area of the Sucusari river basin could be considered primate refuge. Of the remaining hunted area, 16% was hunted relatively little by primate hunters. We suggest that the combination of territoriality and selection against primates creates refuges, mitigating the effects of sustained hunting pressure and contributing to the conservation of these species.

In zoo and laboratory colonies of marmosets and tamarins (Callitrichidae) there has been an increasing need to adopt breeding control methods. In zoos, this need has been driven by a growth in populations. In laboratories, increased interest in control options has followed from the requirement to improve welfare by housing potential breeding animals together. Progestagen-containing contraceptive implants or depot-injections, prostaglandin injection regimes, vasectomy and various group-management methods have been used to control reproduction in marmoset and tamarin colonies. There is a need for advances in control techniques suitable for use in zoos. In the meantime, a policy of selective euthanasia or the use of vasectomy are recommended as control methods. In laboratories, although improved control methods are required, a number of techniques have been found to be satisfactory. When there are surplus marmosets and tamarins, the alternatives for their utilization include movement to other colonies, use for studies within zoos or in laboratories, sale to private keepers or euthanasia. Selling these animals privately is not recommended, except in exceptional circumstances. The preferred control option will differ in each circumstance and guidance is given in this paper.

Use of a privacy panel in the home cage of female pair-housed rhesus monkeys has been reported to increase time spent in close proximity and time spent in affiliative behaviours. In the current study we measured these behaviours in more diverse populations; including male-male and male-female pairs of monkeys actively participating in cognitive experiments. We observed twenty-five pairs of rhesus macaques (Macaca mulatta) both with and without the presence of a privacy divider. Monkeys spent significantly more time in the same half of the pair-cage when the divider was in place. A significant increase in affiliative behaviour was not observed. The effects of privacy dividers previously reported for female monkeys partially extend to male pairs and mixed sex pairs under conditions typical of an active research setting.

It is imperative to provide adequate quantity and quality of space for all captive animals. Yet practically all guidelines on the housing of primates in the laboratory specify minimum cage sizes based solely on body weight. We argue that no single factor, such as body weight, is sufficient to determine cage size. Instead a suite of characteristics should be used that include morphometric, physiological, ecological, locomotor, social, reproductive and behavioural characteristics. Ideally, the primate's age, sex and individual history should also be taken into account. In this paper we compare this suite of characteristics for some commonly used primates whose weights overlap, to illustrate important differences amongst them. For good animal welfare and good quality science it is necessary to be sensitive to such species differences when determining suitable cage sizes.

This study evaluates the methods utilised to release and monitor three troops of rehabilitated vervet monkeys (Chlorocebus aethiops) in South Africa. In all cases, monitoring was poor and conducted over a short time-frame disallowing release outcomes to be fully assessed. Wild troops were present at two of the three locations, casting doubt upon sightings of released monkeys and indicating that the release sites chosen were unsuitable and presented disease risks to the wild vervets. Eighty-three percent of monkeys were unaccounted for at the end of monitoring. Any future releases should make use of radio or GPS collars to track the monkeys, have a planned monitoring schedule covering a period of at least one year, collect detailed data on behaviour, demographics and ecology and should follow the IUCN Guidelines for Non-Human Primate Re-introductions.

Predator–prey dynamics are an important aspect of community ecology, but predation events are often difficult to observe. Among African primates, observations of mammal predation are particularly uncommon and generally restricted to a few ape and cercopithecoid species. I report five observations of mammal predation by golden-bellied mangabeys (Cercocebus chrysogaster) living in rainforest at the LuiKotale study site, Democratic Republic of the Congo. Over 46 all-day follows, mangabeys from one group caught and consumed four duikers (Cephalophinae spp.) and one Alexander’s cusimanse (Crossarchus alexandri). Individuals begged from the feeding individual in three of five observations. I observed one successful attempt at begging, which resulted in an adult female tolerating removal of blue duiker by a juvenile. These are the first detailed observations of mammal predation and food sharing by Cercocebus mangabeys and suggest mammals that feed alongside mangabeys may balance predation risk against social foraging benefits. Food sharing is rarely observed in most cercopithecine monkeys and could provide a useful metric to examine socio-ecological patterns of food acquisition.

The Caatinga of north-eastern Brazil is the largest and most diverse seasonally dry tropical forest in the Americas and is home to numerous endemic species. However, only 1.2% of the area is under full protection, and given the ongoing decline of this biome there is an urgent need to expand the protected area network. The Endangered Caatinga howler monkey Alouatta ululata is almost endemic to the Caatinga, and is a potential umbrella species for the protection of its biodiversity. Using all available distribution data and our own surveys we applied Maxent and Zonation spatial modelling to identify the range of A. ululata, and priority conservation areas for the species, maximizing habitat quality and connectivity, and minimizing conservation constraints. The top 10% priority areas cover 34,400 km2 and mostly coincide with good remnants of Caatinga. Only priority areas in the northern part of the species’ range are protected, so it is essential to create new protected areas in the centre and south of the range. Maxent modelling indicates that the species depends on good tree cover, but even inside protected areas we observed recent deforestation, illustrating the urgency to improve management. Maxent also indicated that aridity limits the species' range, and therefore the ongoing aridification of the Caatinga is a threat to its future. The protection of A. ululata requires establishing new protected areas in priority locations and improving management of existing protected areas. Preservation of priority areas for the Caatinga howler monkey also represents an opportunity for the conservation of other important biodiversity in the region.

The rate of deforestation in the Amazon is increasing. Predictive models estimate that as a result of agricultural expansion 40% of these forests will be lost by 2050. As a consequence the habitat of forest-dwelling species such as the Endangered black-faced black spider monkey Ateles chamek is being lost, particularly along the arc of deforestation in the Brazilian Amazon. We used species distribution modelling to (1) define the distribution of this spider monkey, using environmental predictors, (2) calculate the area of this distribution covered by the protected area network, and (3) calculate the expected loss of the species’ habitat under future scenarios of deforestation. We found that the species occupies only c. 28% of its extent of occurrence. Only 32% of the species’ area of occupancy is legally protected, and the modelling suggests that 31–40% of the species’ habitat will be lost by 2050. We highlight three unprotected regions with extensive forest cover that are predicted to become severely deforested by 2050 as priority regions for expanding the protected area network. We also propose landscape management and restoration in three human-modified regions. Our study provides an example of how species distribution modelling can be applied to assess threats to species and support decision makers in implementing conservation actions.

Madagascar is one of the most threatened biodiversity hotspots, and protection of its biodiversity is becoming increasingly urgent as deforestation of the island continues. For the long-term success of conservation efforts it is essential that key ecological processes, such as seed dispersal, are protected and restored. Therefore, the identification of ecological gaps is a vital task. For Madagascar, only little is known about plant–animal interactions, and traditional methods of ecological research are too time-consuming to provide crucial information about breakdowns in these interactions. To identify likely dispersal gaps we therefore used a theoretical approach to analyse plant–disperser interactions in Madagascar. We used data science tools to impute missing data on relevant plant traits to subsequently predict the most likely dispersal agents for each of Madagascar's endemic plant species. We found that 38% of the endemic species (N = 8,784) are endozoochorous, and among these 26–41% display a primate syndrome and 17–19% a bird syndrome (depending on the definition of syndromes). This lower percentage of endozoochorous species and higher percentage of species with a primate syndrome in Madagascar compared to other tropical areas reflects the unusual disperser guild on the island. Only five bird species but 20 lemur species are frugivorous, and 16 of those lemur species are currently threatened with extinction. The disappearance of frugivorous lemurs would significantly change the vegetation dynamics of Madagascar's ecosystems, and a high proportion of Madagascar's endemic plants would enter an extinction vortex.

Suppose that a colleague proposed a fantastic experiment: to introduce human stem cells into a neonatal mouse so that its entire brain developed into “human-like” neuronal structures. The colleague claimed it would still be a mouse, and that its chimeric brain would be nothing like a “human” one. It would not, as a result, have a moral status beyond its nonhuman animal origins. Thus, the “human neuron mouse” would allow scientists to tinker with human-like neurology in ways that would be precluded if it were a human being, and that would promise to lead to substantial understanding of the destructive and incurable brain diseases that befall humanity. The colleague does admit, however, that for reasons of comparative fidelity, experiments in human patients would be scientifically preferable, although in this case, neither ethically justified nor legally permitted. For that reason, it might be desirable to create a human brain in a nonhuman primate, where it would be more likely that significant human-like neuronal development would occur, but still could not become a person. This article explores the significance of a “human neuron chimpanzee,” and suggests that contradictions in the design of the experiment make it unethical to proceed in either murine or primate models.

We describe morphological and morphometrical characteristics of preantral ovarian follicles from three recently recognized Saimiri species: S. macrodon, S. cassiquiarensis and S. vanzolinii; the last one a threatened species. Ovaries from four adult monkeys were evaluated: one pair from a pregnant S. macrodon, two ovarian pairs from S. cassiquiarensis females (one of them pregnant), and one left ovary from a senile S. vanzolinii, applying classical histology. Follicular preantral population was quantified and morphology and morphometry of primordial, primary and secondary follicles were evaluated. Follicular preantral population varied among species, being 347,153 in the ovaries of the S. macrodon, 270,342 and 278,376 in the ovaries of both adult non-pregnant and pregnant S. cassiquiarensis females, and 28,149 in the ovary from a senile S. vanzolinii. Most follicles were at primordial or transition stages, except for the senile S. vanzolinii female, which presented the lowest percentages of primordial and transition follicles when compared with primary and secondary ones. Most preantral follicles (>70%) were morphologically normal in the ovaries from all studied S. macrodon and S. cassiquiarensis females, but the ovary of the senile S. vanzolinii female presented a significant decrease in the percentage of normal follicles (primordial: 61%, transition: 52%, primary: 54%, and secondary: 48%). In general, follicular diameter increased significantly from primordial to transition, and subsequently from primary to secondary follicles.

The decline of the mongoose lemur Eulemur mongoz has resulted in a change of its conservation status from Vulnerable to Critically Endangered. Assessing the current threats to the species and the attitudes of the people coexisting with it is fundamental to understanding whether and how human impacts may affect populations. A questionnaire-based analysis was used to study the impact of agriculture and other subsistence activities, and local educational initiatives, on lemur abundance, group size and composition in the Comoros. On the islands of Mohéli and Anjouan we recorded 214 lemurs in 63 groups, the size and composition of which depended both on environmental parameters and the magnitude and type of anthropogenic pressure. There was no evidence of an impact of anthropogenic disturbance on abundance. In contrast, group size and composition were sensitive to human impacts. The most important threats were conflicts related to crop raiding, as well as illegal capture and hunting. The promotion of educational activities reduced the negative impact of hunting and illegal activities. These results highlight a need for urgent conservation measures to protect the species.