Trapping, collaring and monitoring the Lorisinae of Asia (Loris, Nycticebus) and Perodicticinae (Arctocebus, Perodicticus) of Africa

Nocturnal animals are difficult to see and follow, especially in dense rainforest conditions. Nocturnal research is fraught with difficulties not encountered by individuals who study animals in the day, from the need for expensive equipment, constant access to power supplies to run lights and potential for increased encounters with dangerous wildlife. The main drawback of nocturnal fieldwork is that it is simply more difficult to find and continuously observe an animal at night. Through hard work and perseverance it is possible to obtain ecological data on lorises and pottos in the absence of radio tracking (e.g. Das et al., 2014; Nekaris, 2001; Pliosungnoen et al., 2010). Much more detail can be obtained, however, through capturing, measuring, collaring and monitoring nocturnal primates. The essential nature of radio tracking for the study of the behaviour and ecology of nocturnal primates has been recognised since the 1970s (e.g. Charles-Dominique, 1977a; Charles-Dominique and Bearder, 1979), and is by most researchers considered a must for thorough research (Sterling et al., 2000). Radio-tracking studies of lorises and pottos remain limited (2000; Millspaugh and Marzluff, 2001). In this chapter, we review the methods for trapping and collaring slow lorises and pottos, as well as provide a case study of the importance of red light for observing their behaviour in a humane and productive manner

Is tickling torture? Assessing welfare towards slow lorises (Nycticebus spp) within Web 2.0 videos

Videos, memes and images of pet slow lorises have become increasingly popular on the Internet. Although some video sites allow viewers to tag material as ‘animal cruelty', no site has yet acknowledged the presence of cruelty in slow loris videos. We examined 100 online videos to assess whether they violated the ‘five freedoms' of animal welfare and whether presence or absence of these conditions contributed to the number of thumbs up and views received by the videos. We found that all 100 videos showed at least 1 condition known as negative for lorises, indicating absence of the necessary freedom; 4% showed only 1 condition, but in nearly one third (31.3%) all 5 chosen criteria were present, including human contact (57%), daylight (87%), signs of stress/ill health (53%), unnatural environment (91%) and isolation from conspecifics (77%). The public were more likely to like videos where a slow loris was kept in the light or displayed signs of stress. Recent work on primates has shown that imagery of primates in a human context can cause viewers to perceive them as less threatened. Prevalence of a positive public opinion of such videos is a real threat towards awareness of the conservation crisis faced by slow lorises

Foraging behaviour of the slender loris (Loris lydekkerianus lydekkerianus): implications for theories of primate origins

Abstract Members of the Order Primates are characterised by a wide overlap of visual fields or optic convergence. It has been proposed that exploitation of either insects or angiosperm products in the terminal branches of trees, and the corresponding complex, three-dimensional environment associated with these foraging strategies, account for visual convergence. Although slender lorises (Loris sp.) are the most visually convergent of all the primates, very little is known about their feeding ecology. This study, carried out over 10 ½ months in South India, examines the feeding behaviour of L. lydekkerianus lydekkerianus in relation to hypotheses regarding visual predation of insects. Of 1238 feeding observations, 96% were of animal prey. Lorises showed an equal and overwhelming preference for terminal and middle branch feeding, using the undergrowth and trunk rarely. The type of prey caught on terminal branches (Lepidoptera, Odonata, Homoptera) differed significantly from those caught on middle branches (Hymenoptera, Coleoptera). A two-handed catch accompanied by bipedal postures was used almost exclusively on terminal branches where mobile prey was caught, whereas the more common capture technique of one-handed grab was used more often on sturdy middle branches to obtain slow moving prey. Although prey was detected with senses other than vision, vision was the key sense used upon the final strike. This study strongly supports the notion that hunting for animal prey was a key ecological determinant in selecting for visual convergence early on in primate evolution. The extreme specialisations of slender lorises, however, suggest that early primates were not dedicated faunivores and lend further support to the emerging view that both insects and fruits were probably important components of the diet of basal primates, and that exploitation of fruits may account for other key primate traits

Vertical clingers and gougers: rapid acquisition of adult limb proportions facilitates feeding behaviours in young Javan slow lorises (Nycticebus javanicus)

Animals of all ages need to access essential food resources, either on their own or with the assistance of conspecifics. Rapid physical and behavioural development is one strategy to help young animals reach adulthood. Specialized gum-feeding mammals exploit a food type that is relatively difficult to access and digest and must possess the appropriate adaptions to access large vertical substrates, i.e. tree trunks. Unlike other gum feeding mammals, the Javan slow loris (Nycticebus javanicus) lacks physical structures, such as keeled nails or claws, which animals commonly use to secure themselves to large vertical substrates. To understand how slow lorises of all ages exploit gum, we examined their vertical gouging posture, locomotor behaviour, habitat use during feeding, and their morphometric measures across three age classes (adult, sub-adult, juvenile). Using data collected in Cipaganti, Java, Indonesia between April 2012 and April 2016, we found that individuals of N. javanicus rely on their hand, foot, and limb morphology to maintain vertical gouging postures, in place of claws or keeled nails. Locomotor behaviour, position in tree, and tree DBH showed no significant difference across age classes while feeding. Juveniles were indistinguishable from adults and sub-adults in regards to limb proportion indices, lower leg length, hand span and foot span. Some morphometric measures scaled isometrically e.g. arm length, but those highlighted during prolonged vertical postures scaled allometrically e.g. leg, hand, and foot measures. These findings suggest that the rapid behavioural and physical development of key features may act as an ontogenetic adaptation to facilitate access to a stable food resource at a young age. The Javan slow loris exemplifies the complex relationship that exists between an animal’s diet and the specializations that facilitate access to these food resources

Does toxic defence in Nycticebus spp. relate to ectoparasites? The lethal effects of slow loris venom on arthropods

a b s t r a c t The venom produced by slow lorises (Nycticebus spp.) is toxic both intra-and inter-specifically. In this study we assessed the ecoparasite repellent properties of their venom. We tested venom from two Indonesian slow loris species: Nycticebus javanicus and Nycticebus coucang. Arthropods directly exposed to brachial gland secretions mixed with saliva from both species were immediately impaired or exhibited reduced activity (76%), and often died as a result (61%). We found no significant difference in the result of 60-min trials between N. coucang and N. javanicus [X 2 (1, n ¼ 140) ¼ 2.110, p ¼ 0.3482]. We found evidence that the degree of lethality of the venom varies according to the arthropod taxa to which it is exposed. While most maggots (84%) were initially impaired from the venom after 10 min, maggots died after a 1 h trial 42% of the time. In contrast, at the end of 1 h trial, spiders died 78% of the time. For all arthropods, the average time to death from exposure was less than 25 min (M ¼ 24.40, SD ¼ 22.60). Ectoparasites including ticks, members of the arachnid order, are known to transmit pathogens to hosts and may be an intended target of the toxic secretions. Our results suggest that one function of slow loris venom is to repel parasites that affect their fitness, and that their topical anointing behaviour may be an adaptive response to ectoparasites

Calling patterns of Western purple-faced langurs (Mammalia: Primates: Cercopithecidea: Trachypitchecus vetulus nestor) in a degraded human landscape in Sri

Abstract The study of calling patterns is a useful non-invasive method for determining population densities and the taxonomic relationships of rare or cryptic animal species. The Western purple-faced langur Trachypithecus vetulus nestor, endemic to Sri Lanka's lowland rainforests, is severely impacted by forest fragmentation, with most remaining populations living almost completely in home gardens. Due to their shy nature, little is known about the behaviour of this subspecies; analysing the regular loud calls emitted by these langurs could allow for improvement of census techniques, clarification of their taxonomy, and an understanding of the impact of forest destruction on their behaviour. In 2007, we recorded the calling patterns of five male T. v. nestor at Talangama Wetlands. Time, duration, weather conditions, and stimulant of 253 calls were noted. Loud calls comprised three structural units: harsh barks, whoops and residuals. The average call contained 4 phrases and 3.8 residuals, was 38 seconds in length, had an average maximum frequency of 3.5 kHz, a formant frequency of 0.36 kHz, and a fundamental frequency of 0.2 kHz. Significant differences were found between individuals for the number of phrases and residuals within a call, two different phrase lengths, the formant frequency and the fundamental frequency. The earliest call occurred at 05:27 hrs, while the latest was made at 17:57 hrs. The greatest percentage of calls (73.5%) was heard in the morning (05:00-09:59 hrs), mostly stimulated by territorial battles with neighbouring troops. These results show that vocalisations can be used to distinguish individual males; as langurs are more often heard than seen, and most troops contain only a single adult male, vocalisations may be used to determine the number of troops in an area. Calls of this taxon also differed from the other subspecies, suggesting that they may be used to distinguish subspecies and their boundaries. Finally, calling behaviour differed from other subspecies. Deforestation may be a direct cause of different calling patterns. These baseline data form a valuable starting point for further studies of this Critically Endangered primate

Preserving Preuss’s red colobus (Piliocolobus preussi); an analysis of hunting and changing perceptions of primates in Ikenge-Bakoko, Cameroon

The futures of nonhuman primate species and human communities in shared landscapes rely on our ability to engage with and understand the complex histories and multiscalar aspects of human–animal relationships. We use the Critically Endangered Preuss’s red colobus (Piliocolobus preussi) as a case study to examine the important ways in which histories of multiscalar human–primate interactions play out in the village of Ikenge-Bakoko, Korup National Park, Cameroon. We contextualize ethnographic and catchment data from adult men (N = 32) and women (N = 31) within long-term diurnal primate monitoring datasets to better understand the relationships among hunting practices, local perceptions of diurnal primates, populations of P. preussi, and conservation management. Our data indicate a disconnect between local cultural definitions of “hunter” and Western assumptions as to the makeup and nature of this and other categories. We show that such contradictions can have negative outcomes for conservationists seeking to turn the science of establishing accurate off-take rates of prey species into practical management solutions. Using a single village as a focal point, we highlight the importance of an ethnoprimatological approach to understanding the intricate entanglements among conservation histories, subsistence strategies, and human and nonhuman primate lives. The application of ethnoprimatology is critical for twenty-first century primatologists who must navigate conservation concerns while also acknowledging and valuing the experiences of the human communities living alongside the primates we study

Checkerboard Patterns, Interspecific Competition, and Extinction: Lessons from Distribution Patterns of Tarsiers (Tarsius) and Slow Lorises (Nycticebus) in Insular Southeast Asia

Tarsiers (Tarsius) and slow lorises (Nycticebus) are the only extant nocturnal primates occurring in Southeast Asia. Harcourt (1999) hypothesized that in insular Southeast Asia, slow lorises and tarsiers showed a checkerboard distribution on 12 small (<12,000 km2) islands, i.e., only one or the other occurs, and attributed this to extreme levels of competition between these 2 largely faunivorous primates. Further, he predicted slow lorises were able to persist on smaller islands than tarsiers. We re-evaluated these findings using an expanded dataset including 49 islands where tarsiers or slow lorises occur. Tarsiers and slow lorises live on islands of similar size (median size of ca. 300–900 km2), and both taxa inhabit an equal proportion of small, medium, and large islands. On small islands within their area of sympatry tarsiers occur on 1 island, slow lorises on 8, both genera on 3, and we can assume they have become extinct from 11 small islands since the Last Glacial Maximum. Sizes of islands where tarsiers or slow lorises have become extinct do not differ from islands where they are still extant. We show that slow lorises occur on more islands in insular Southeast Asia than perhaps previously assumed, but these islands are not smaller on average than islands where tarsiers occur. A checkerboard distribution between these taxa is not evident. More studies are needed at the macroecological level to assess the importance of biogeographic history in explaining their present-day distribution patterns

Slow lorises (Nycticebus spp.) display evidence of handedness in the wild and in captivity

It has been suggested that strepsirrhines (lemurs, lorises, and galagos) retain the more primitive left hand preference, whilst monkeys and apes more regularly display a right hand preference at the individual-level. We looked to address questions of laterality in the slow loris (Nycticebus spp.) using spontaneous observations of seven wild individuals, unimanual tests in six captive individuals, and photos of 44 individuals in a bilateral posture assessing handedness at the individual- and group-level. During the unimanual reach task, we found at the individual-level, only four slow lorises showed a hand use bias (R: 3, L:1), Handedness index (HI) ranged from -0.57-1.00. In the wild unimanual grasp task we found at the individual-level two individual showed a right-hand bias, the HI ranged from -0.19-0.70. The bilateral venom pose showed a trend toward a right hand dominant grip in those photographed in captivity, but an ambiguous difference in wild individuals. There are many environmental constraints in captivity that wild animals do not face, thus data collected in wild settings are more representative of their natural state. The presence of right-handedness in these species suggest that there is a need to re-evaluate the evolution of handedness in primates