Reducing stress and stereotypic behaviors in captive female pygmy slow lorises (Nycticebus pygmeaus)

Improving captive conditions of pygmy slow lorises (Nekaris and Nijman have recently suggested that the pygmy slow loris should be called the pygmy loris and is distinctive enough to warrant a new genus, Xanthonycticebu) (Nycticebus pygmeaus) poses many challenges because detailed aspects of their lives in the wild are incomplete. This hinders efforts to replicate sustainable environments for them. To improve their well-being in captivity, eight rescued female pygmy slow lorises at the Japan Monkey Center (JMC) were socially housed in two types of groups following their solitary housing: two pairs and one group of four individuals. They spent much of their time in affiliative behaviors, as well as sharing sleeping sites after placement in a social group. The purpose of my study was to examine whether social housing helped in reducing stress by comparing fecal glucocorticoids and stereotypic behaviors when housed alone and when with conspecifics. Overall, the levels of fecal glucocorticoids were significantly lower when socially housed than when kept alone. One individual exhibited stereotypic behavior when housed alone, but this behavior disappeared after social housing. These findings support recent evidence that pygmy slow lorises are social animals and will benefit from group housing in captivity. We conclude that social housing of pygmy slow lorises improves their well-being by reducing stress levels, and that their group housing in captivity can provide dividends for the conservation of this endangered nocturnal primate because lorises intended for release should find it easier to adapt to natural conditions.

Disgust in animals and the application of disease avoidance to wildlife management and conservation

Disgust is an adaptive system hypothesized to have evolved to reduce the risk of becoming sick. It is associated with behavioural, cognitive and physiological responses tuned to allow animals to avoid and/or get rid of parasites, pathogens and toxins. Little is known about the mechanisms and outcomes of disease avoidance in wild animals. Furthermore, given the escalation of negative human-wildlife interactions, the translation of such knowledge into the design of evolutionarily relevant conservation and wildlife management strategies is becoming urgent. Contemporary methods in animal ecology and related fields, using direct (sensory cues) or indirect (remote sensing technologies and machine learning) means, provide a flexible toolbox for testing and applying disgust at individual and collective levels. In this review/perspective paper, we provide an empirical framework for testing the adaptive function of disgust and its associated disease avoidance behaviours across species, from the least to the most social, in different habitats. We predict various trade-offs to be at play depending on the social system and ecology of the species. We propose five contexts in which disgust-related avoidance behaviours could be applied, including endangered species rehabilitation, invasive species, crop-raiding, urban pests and animal tourism. We highlight some of the perspectives and current challenges of testing disgust in the wild. In particular, we recommend future studies to consider together disease, predation and competition risks. We discuss the ethics associated with disgust experiments in the above contexts. Finally, we promote the creation of a database gathering disease avoidance evidence in animals and its applications.

Molecular Phylogenetic Relationships and Unveiling Novel Genetic Diversity among Slow and Pygmy Lorises, including Resurrection of Xanthonycticebus intermedius

Genetic analysis of historical museum collections presents an opportunity to clarify the evolutionary history of understudied primate groups, improve taxonomic inferences, and inform conservation efforts. Among the most understudied primate groups, slow and pygmy lorises (genera Nycticebus and Xanthonycticebus) are nocturnal strepsirrhines found in South and Southeast Asia. Previous molecular studies have supported five species, but studies using morphological data suggest the existence of at least nine species. We sequenced four mitochondrial loci, CO1, cytb, d-loop, and ND4, for a total of 3324 aligned characters per sample from 41 historical museum specimens for the most comprehensive geographic coverage to date for these genera. We then combined these sequences with a larger dataset composed of samples collected in Vietnam as well as previously published sequences (total sample size N = 62). We inferred phylogenetic relationships using Bayesian inference and maximum likelihood methods based on data from each locus and on concatenated sequences. We also inferred divergence dates for the most recent common ancestors of major lineages using a BEAST analysis. Consistent with previous studies, we found support for Xanthonycticebus pygmaeus as a basal taxon to the others in the group. We also confirmed the separation between lineages of X. pygmaeus from northern Vietnam/Laos/China and southern Vietnam/Cambodia and included a taxonomic revision recognizing a second taxon of pygmy loris, X. intermedius. Our results found support for multiple reciprocally monophyletic taxa within Borneo and possibly Java. The study will help inform conservation management of these trade-targeted animals as part of a genetic reference database for determining the taxonomic unit and provenance of slow and pygmy lorises confiscated from illegal wildlife trade activities.

A new genus name for pygmy lorises, Xanthonycticebus gen. nov. (Mammalia, primates)

Lorisiformes are nocturnal primates from Africa and Asia with four genera, with two (Arctocebus and Loris), three (Perodicticus) and nine (Nycticebus) recognised species. Their cryptic lifestyle and lack of study have resulted in an underappreciation of the variation at the species and genus level. There are marked differences between the pygmy slow loris Nycticebus pygmaeus and the other Nycticebus species and, in the past, several authors have suggested that these may warrant recognition at the generic level. We here combine morphological, behavioural, karyotypical and genetic data to show that these contrasts are, indeed, significantly large and consistent. We propose Xanthonycticebus gen. nov. as a new genus name for the pygmy slow lorises and suggest a common name of pygmy lorises. Based on analysis of complete mitochondrial DNA sequences, we calculate the divergence of pygmy from slow lorises at 9.9–10.0%. The median date, calculated for the divergence between Xanthonycticebus and Nycticebus, is 10.5 Mya (range 4.9–21.0 Mya). Xanthonycticebus differs from Nycticebus by showing sympatry with other slow loris species, by habitually giving birth to twins, by showing seasonal body mass and whole body coat colour changes (absent in other species living at similar latitudes) and a multi-male, multi-female social system. Pygmy lorises are easily recognisable by the absence of hair on their ears and more protruding premaxilla. Xanthonycticebus is threatened by habitat loss and illegal trade despite legal protection across their range and all slow lorises are listed on appendix 1 of CITES. The suggested nomenclatural changes should not affect their legal status.

A pain in the neck: weak links are not a reliable release mechanism for radio-collars

Collars are an attachment method commonly used to mount data collection devices on wildlife. Removal of collars at the completion of a data collection period is a high priority for the purpose of animal welfare, but retrieval of collars can often be difficult. Weak links or other drop-off devices are used by researchers with the intention of improving collar retrieval rates, and for mitigation of animal welfare risks associated with collar entanglement. However, the design and effectiveness of such devices is not regularly reported in detail in the literature. We surveyed wildlife researchers to collate and communicate their experiences with weak links, and assess their attitudes towards collaring Australian mammals in the 35–5500 g weight range. Forty-five researchers responded to the survey, of whom 25 had used weak links in at least one study. There was very little consistency between the performances of weak links, with researchers finding them effective in less than half of the scenarios reported upon. Outcomes varied depending on the type of material used for the link, the species being collared, and the environmental conditions under which the collars were being deployed. We recommend (1) researchers test weak links prior to deployment; (2) users to not rely upon weak links as the primary method of collar retrieval; and (3) continued communication of design and outcomes of all radio-collars deployed including those with weak links.

The effect of pre-release captivity on post-release performance in reintroduced eastern bettongs Bettongia gaimardi

Reintroductions are used to re-establish populations of species within their indigenous range, but their outcomes are variable. A key decision when developing a reintroduction strategy is whether to include a temporary period of confinement prior to release. Pre-release confinement is primarily used for the purpose of quarantine or as a delayed-release tactic to influence the performance or behaviour of founders post-release. A common difference between these approaches is that quarantine tends to be conducted in ex situ captivity, whereas delayed releases tend to involve in situ confinement at the release site. Although these practices are commonly viewed independently, it may be possible for a single confinement period to be used for both purposes. We tested whether temporarily holding wild eastern bettongs Bettongia gaimardi in ex situ captivity for 95–345 days prior to release (delayed release) influenced their body mass, pouch occupancy or survival during the first 1.5 years post-release, compared to founders released without confinement (immediate release). Our results suggest that exposing founders to captivity did not alter their body mass or performance post-release, despite being heavier and having fewer pouch young when released. We conclude that, for this species, ex situ captivity does not represent a tactical opportunity to improve post-release performance but can be used for quarantine without affecting the probability of establishment.