A comparison of nocturnal primate behavior in exhibits illuminated with red and blue light

Skyglow facilitates prey detection in a crepuscular insectivore: Distant light sources create bright skies

Light profoundly shapes ecosystems, influencing the behaviour and niche specialisation of many species. This is especially true for visual predators, particularly crepuscular and nocturnal animals, whose foraging depends on adequate illumination. Despite this, research on how animals perceive light sources and position themselves relative to these sources is scarce. Using a modified dead-reckoning protocol based on GPS, accelerometer, and magnetic compass data, we investigated the body orientation of foraging European Nightjars (Caprimulgus europaeus, hereafter nightjar) to determine their line of sight relative to bright sections of the nocturnal sky, created by natural or artificial light. We found that nightjars are more likely to align themselves with brighter sections of the sky, although not necessarily with the brightest patch. On full moon nights, they positioned the moon within their line of sight when it was low on the horizon, but this likelihood decreased as the moon rose higher. During other moon phases, the likelihood of having the moon within line of sight increased linearly with moon altitude. During moonless parts of the night, nightjars appeared to use skyglow as a background for prey detection, but only when it was sufficiently bright. When both moonlight and skyglow were present, nightjars showed a preference for moonlight. This study shows that European Nightjars use illuminated sections of the sky, including skyglow, as bright backgrounds to detect flying prey. This suggests that, in the absence of the moon, nightjars can actively take advantage of this form of light pollution while foraging. However, the success of their hunting under skyglow-induced lighting remains unclear. We hypothesise that the effectiveness of these backgrounds depends on their brightness and colour composition. Further research is needed to better understand the complex dynamics of contrast detection under varying lighting conditions.

Welfare and Enrichment of Managed Nocturnal Species, Supported by Technology

This paper addresses the potential for technology to support husbandry and enrichment opportunities that enhance the welfare of zoo and sanctuary-housed nocturnal and crepuscular species. This topic was investigated through the medium of a multidisciplinary workshop (Moon Jam) that brought together species experts, zoo designers, Animal-Computer Interaction researchers and post-graduate students in collaborative discussions and design sessions. We explain the context through an examination of existing research and current practices, and report on specific challenges raised and addressed during the Moon Jam, highlighting and discussing key themes that emerged. Finally, we offer a set of guidelines to support the integration of technology into the design of animal husbandry and enrichment that support wellbeing, to advance the best practices in keeping and managing nocturnal and crepuscular animals.

Light pollution and habitat fragmentation in the grey mouse lemur

Light pollution, by changing organisms' behavior, affects locomotion, migration and can ultimately fragment the habitat. To investigate the effects of light pollution on habitat fragmentation, we conducted an experimental study on a nocturnal and photosensitive primate, the grey mouse lemur (Microcebus murinus). Twelve males were housed individually in an apparatus with two cages connected by two corridors, opaque and transparent. During 4 nights, the transparent corridor was illuminated by specific light intensities: 0 lx, 0.3 lx, 20 lx and 51.5 lx corresponding respectively to total darkness, full moon, minimal intensity recommended by the European standard EN-13201 on public lighting, and to light pollution recorded in an urban area. Each night, general activity, use of corridors and cage occupancy were recorded using an infrared camera. For the first time in a nocturnal primate, results demonstrate that light pollution changes the preference of use of corridors, modifies the locomotor pattern and limits the ability of animals to efficiently exploit their environment according to a light intensity-dependent relationship. However, results indicate that a dark corridor allows partial compensation partly preserving general activities. This study highlights the necessity to consider light pollution during the implementation of conservation plans and the relevance of nocturnal frames.

Nesfatin-1 protects the reproductive health of male Sprague Dawley rats exposed to blue and white LED lights

There is little information on the effects of exposure to light emitting diode (LED) illumination on the welfare of laboratory animals. Nesfatin-1, a satiety-regulation peptide present in various tissues, is found in the central nervous system and participates in the stress response. The present study investigated whether exposure to blue and white LED lights for 14 weeks affected growth and reproductive, biochemical and histopathological parameters in male Sprague Dawley (SD) rats as well as whether subcutaneous (SC) injection of nesfatin-1 (0.5 mg/kg bodyweight) in the last two weeks of the experimental period alleviated these effects. Forty male SD rats (21 days of age) were randomly allotted to 6 groups. The animals were exposed to routine fluorescent light (the control [C] and control + sesame oil [CS] groups) or blue/white LEDs (the blue-LED and white-LED groups), accompanied by nesfatin-1 administration (the blue-LED-N1 and white-LED-N1 groups). White-LED rats had significantly higher testis weights (p < 0.05) than control and blue-LED rats. Serum melatonin levels were significantly lower in blue-LED rats, but nesfatin-1 injection rescued melatonin levels in blue-LED-N1 rats (p < 0.05). Blue-LED rats showed the highest serum nesfatin-1 levels, but nesfatin-1 injection decreased nesfatin-1 levels in blue-LED-N1 rats (p < 0.0001). Blue-LED rats showed a significant reduction in sperm motility compared to the other groups (p < 0.0001). White and blue LED exposure caused significant negative histopathological changes in the testes, but nesfatin-1 administration reduced edema in the intertubular spaces, hyperemia in the interstitial cells, degeneration of spermatocytes and thinning of the tubular wall in the testicular tissues; these restorative effects were larger in blue-LED-N1 rats than white-LED-N1 rats. Blue and white LED exposures had negative effects on melatonin levels, testis weights and tissue health. Nesfatin-1 alleviated some of the negative effects of LED lighting.

Promoting Good Nonhuman Primate Welfare outside Regular Working Hours

Promoting good primate welfare outside of daylight hours is an important task. The responsibility to provide a complex environment and environmental enrichment is an essential element of primate wellbeing programs that should be approached from a 24-h perspective and planned according to the species and individual needs, including giving animals the ability to interact with and control their environment during hours when animal care staff are not present. One must be aware, however, that their needs may differ at night-time from their care needs during the day when staff are present. Assessing welfare and providing enrichment during times when staff are not on hand can be achieved through the use of a variety of technologies, such as night-view cameras, animal-centred technologies, and data loggers. This paper will address the relevant topics concerning the care and welfare of primates during off-hours, and the use of related technologies to facilitate and assess wellbeing at these times.

A light-exploiting insectivorous bat shows no melatonin disruption under lights with different spectra

Natural light-dark cycles synchronize an animal's internal clock with environmental conditions. The introduction of artificial light into the night-time environment masks natural light cues and has the potential to disrupt this well-established biological rhythm. Nocturnal animal species, such as bats, are adapted to low light conditions and are therefore among the most vulnerable to the impacts of artificial light at night (ALAN). The behaviour and activity of insectivorous bats is disrupted by short-wavelength artificial light at night, while long-wavelength light is less disruptive. However, the physiological consequences of this lighting have not been investigated. Here, we examine the effect of LEDs with different spectra on urinary melatonin in an insectivorous bat. We collected voluntarily voided urine samples from Gould's wattled bats (Chalinolobus gouldii) and measured melatonin-sulfate under ambient night-time conditions (baseline) and under red (λP 630 nm), amber (λP 601 nm), filtered warm white (λP 586 nm) and cool white (λP 457 nm) LEDs. We found no effect of light treatment on melatonin-sulfate irrespective of spectra. Our findings suggest that short-term exposure to LEDs at night do not disrupt circadian physiology in the light-exploiting Gould's wattled bat.

Space, time, and context drive anticipatory behavior: Considerations for understanding the behavior of animals in human care

Animal-based measures reflecting the welfare state of individuals are critical for ensuring the well-being of animals under human care. Anticipatory behavior is one potential animal-based measure that has gained traction in recent years, as it is theorized to relate to animals' reward sensitivity. It is of particular interest as an assessment for animals living under human care, as the predictability of the captive environment lends itself to the development of this class of behaviors. Animals are likely to exhibit anticipation in locations related to the anticipated event, often in temporally predictable time frames, and before specific contexts they experience in their day-to-day management. In this sense and under certain circumstances, anticipatory behaviors are likely to drive observed behavioral or space use patterns of animals under human care. Drawing conclusions from such data without identifying anticipation may result in misleading conclusions. Here we discuss how space, time, and context are related to patterns of anticipatory behaviors in animals under human care, how unidentified anticipation may alter conclusions regarding animal behavior or welfare under certain circumstances.

Training in the Dark: Using Target Training for Non-Invasive Application and Validation of Accelerometer Devices for an Endangered Primate (Nycticebus bengalensis)

Simple Summary

Recent advances in technology allow for the study of animal behaviours through indirect observations. This facilitates research on cryptic animals for which direct observations may miss a considerable portion of their activity. The validity of accelerometers in obtaining accurate animal behaviours, however, needs to be tested before collecting data in the wild. Modern zoos offer excellent opportunities for researchers to test field techniques in a safe setting. Here, we describe a non-invasive training program to attach an accelerometer to an individual Bengal slow loris at the Shaldon Wildlife Trust. This training took 39 15-min sessions and allowed for the attachment of the accelerometer for validation with reduced stress for the animal. We also collected videos to associate to accelerometer data to estimate the accuracy of accelerometers in identifying the behaviours of Bengal slow loris. The accuracy was above 80% with some of the behaviours that were clearly identified (e.g., resting: 99.8%), while others were more difficult to discern (e.g., suspensory walk, a locomotion behaviour, was discerned only 60.3% of times from other behaviours). The non-invasive training and accelerometer validation can be used on similar species before using accelerometers in the wild.

Abstract

Accelerometers offer unique opportunities to study the behaviour of cryptic animals but require validation to show their accuracy in identifying behaviours. This validation is often undertaken in captivity before use in the wild. While zoos provide important opportunities for trial field techniques, they must consider the welfare and health of the individuals in their care and researchers must opt for the least invasive techniques. We used positive reinforcement training to attach and detach a collar with an accelerometer to an individual Bengal slow loris (Nycticebus bengalensis) at the Shaldon Wildlife Trust, U.K. This allowed us to collect accelerometer data at different periods between January–June 2020 and January–February 2021, totalling 42 h of data with corresponding video for validation. Of these data, we selected 54 min where ten behaviours were present and ran a random forest model. We needed 39 15-min sessions to train the animal to wear/remove the collar. The accelerometer data had an accuracy of 80.7 ± SD 9.9% in predicting the behaviours, with 99.8% accuracy in predicting resting, and a lower accuracy (but still >75% for all of them apart from suspensory walk) for the different types of locomotion and feeding behaviours. This training and validation technique can be used in similar species and shows the importance of working with zoos for in situ conservation (e.g., validation of field techniques).

A Systematic Review for Establishing Relevant Environmental Parameters for Urban Lighting: Translating Research into Practice

The application of lighting technologies developed in the 20th century has increased the brightness and changed the spectral composition of nocturnal night-time habitats and night skies across urban, peri-urban, rural, and pristine landscapes, and subsequently, researchers have observed the disturbance of biological rhythms of flora and fauna. To reduce these impacts, it is essential to translate relevant knowledge about the potential adverse effects of artificial light at night (ALAN) from research into applicable urban lighting practice. Therefore, the aim of this paper is to identify and report, via a systematic review, the effects of exposure to different physical properties of artificial light sources on various organism groups, including plants, arthropods, insects, spiders, fish, amphibians, reptiles, birds, and non-human mammals (including bats, rodents, and primates). PRISMA 2020 guidelines were used to identify a total of 1417 studies from Web of Science and PubMed. In 216 studies, diverse behavioral and physiological responses were observed across taxa when organisms were exposed to ALAN. The studies showed that the responses were dependent on high illuminance levels, duration of light exposure, and unnatural color spectra at night and also highlighted where research gaps remain in the domains of ALAN research and urban lighting practice. To avoid misinterpretation, and to define a common language, key terminologies and definitions connected to natural and artificial light have been provided. Furthermore, the adverse impacts of ALAN urgently need to be better researched, understood, and managed for the development of future lighting guidelines and standards to optimize sustainable design applications that preserve night-time environment(s) and their inhabiting flora and fauna.

A review of research on the distribution, ecology, behaviour, and conservation of the Slender Loris Loris lydekkerianus (Mammalia: Primates: Lorisidae) in India

The Slender Loris in India includes two subspecies, the Mysore Slender Loris and the Malabar Slender Loris, with unidentified populations at overlapping ranges of the subspecies. Prior to 1996, the knowledge on Indian lorises was mostly limited to laboratory studies, or some anecdotes from the wild. Since late 1990, several intensive field studies have been carried out which informed about the status, ecology, behaviour, conservation issues, and management of the Slender Loris in India. Here, we review all these studies, discuss the major findings and identify directions for future research. 

Social relationships among captive male pygmy slow lorises (Nycticebus pygmaeus): Is forming male same-sex pairs a feasible management strategy?

Little is known about the social behavior of pygmy slow lorises, in particular, the social relationships of same-sex individuals have rarely been investigated. The Slow Loris Conservation Center was built at the Japan Monkey Center to enhance the welfare of confiscated slow lorises, promote their conservation, improve public education, and perform scientific research on the species. In the course of improving housing conditions, several same-sex pairs of pygmy slow lorises were formed. We monitored their behaviors and fecal glucocorticoid metabolite (FGM) levels to understand whether male same-sex pairings could be a feasible management strategy. The subjects were 10 male and 6 female lorises for comparison, all of whom were over 5 years old. We successfully formed five pairs of male lorises after eight formation attempts. Male pairs initially showed some aggressive behaviors; however, the rate decreased approximately 10 days after introduction. All of the male pairs eventually exhibited extensive affiliative social behaviors, including allogrooming and social play, during the dark (active) phase, and sleep site sharing during the light (inactive) phase. The rate of sleep site sharing during the light phase was higher than expected, suggesting that the pairs preferred to stay near each other. There was no evidence of increased stress after a long period of male-male social housing. Female same-sex pairs and male-female pairs demonstrated a high level of affiliative behaviors right after the introduction. These results highlight the flexibility and high sociability of this species and indicate that such same-sex pairings are a feasible option for their social management.

Mapping Shade Availability and Use in Zoo Environments: A Tool for Evaluating Thermal Comfort

For many species in zoos, particularly megafauna vulnerable to heat stress, shade is a key environmental resource. However, shade availability has received comparatively less attention than other aspects of the zoo environment. In this study, we share a simple low-cost approach that we applied to document shade availability across 33 zoo enclosures. We then combined these assessments with behavioral observations of enclosure use and shade-seeking behavior during summer months in a case study focused on Sichuan takin (Budorcas taxicolor tibetana) (n = 3), a large cold-adapted bovid. Behavioral observations were conducted before and after installation of a shade sail for the takin. Results indicated that shade availability varied widely across zoo enclosures, with the percent of shaded space ranging from 85 % to 22 % across enclosures during summer months. Shade was a dynamic resource and increased throughout the year and fluctuated across the day, with the least shade available midday. Takin showed general preferences for shaded areas near the walls of their enclosure but were observed using newly available shade from the shade sail after its installation. These accessible methods can be easily applied to assess shade within existing enclosures, evaluate enclosure modifications, and provide guidance for the design of new enclosures.

Advances in Applied Zoo Animal Welfare Science

Nonhuman animal welfare science is the scientific study of the welfare state of animals that attempts to make inferences about how animals feel from their behavior, endocrine function, and/or signs of physical health. These welfare measurements are applicable within zoos yet inherently more complex than in farms and laboratories. This complexity is due to the vast number of species housed, lack of fundamental biological information, and relatively lower sample sizes and levels of experimental control. This article summarizes the invited presentations on the topic of "Advances in Applied Animal Welfare Science," given at the Fourth Global Animal Welfare Congress held jointly by the Detroit Zoological Society and the World Association of Zoos and Aquariums in 2017. The article focuses on current trends in research on zoo animal welfare under the following themes: (a) human-animal interactions and relationships, (b) anticipatory behavior, (c) cognitive enrichment, (d) behavioral biology, and (e) reproductive and population management. It highlights areas in which further advancements in zoo animal welfare science are needed and the challenges that may be faced in doing so.

The effect of supplementary ultraviolet wavelengths on broiler chicken welfare indicators

Qualities of the light environment are important for good welfare in a number of species. In chickens, UVA light is visible and may facilitate flock interactions. UVB wavelengths promote endogenous vitamin D synthesis, which could support the rapid skeletal development of broiler chickens. The aim of the study was to investigate the impacts of Ultraviolet wavelengths (UV) on welfare indicators in broiler chickens. Day-old Ross 308 birds reared under commercially representative conditions were randomly assigned to one of three lighting treatments: A) White Light Emitting Diode (LED) and supplementary UVA LED lighting (18-hour photoperiod); B) White LED with supplementary UVA and UVB fluorescent lighting providing 30 micro watts/cm2 UVB at bird level (on for 8 h of the total photoperiod to avoid over-exposure of UVB); C) White LED control group, representative of farm conditions (18-hour photoperiod). Welfare indicators measured were; feather condition (day 24, n = 546), tonic immobility duration (day 29, n = 302), and gait quality, using the Bristol Gait Score (day 31, n = 293). Feather condition was improved in male broilers in the UVA treatment (A), compared to the control treatment (C). Birds in the UVA treatment had shorter tonic immobility durations compared to the control treatment (C), suggesting lower fearfulness. Broilers reared in UVA (A) and UVA + UVB (B) had better Bristol Gait Scores compared to the control (C). Together these results suggest UV may be beneficial for broiler chicken welfare. While treatment A and B both provided UVA, the improvements in welfare indicators were not consistent, which may be due to exposure time-dependent beneficial effects of UVA. The modification of commercial lighting regimes to incorporate UVA wavelengths for indoor-reared broiler chickens would be an achievable change with significant positive impacts on bird welfare.