The Tongue in Three Species of Lemurs: Flower and Nectar Feeding Adaptations

The mobility of the primate tongue allows for the manipulation of food, but, in addition, houses both general sensory afferents and special sensory end organs. Taste buds can be found across the tongue, but the ones found within the fungiform papillae on the anterior two thirds of the tongue are the first gustatory structures to come into contact with food, and are critical in making food ingestion decisions. Comparative studies of both the macro and micro anatomy in primates are sparse and incomplete, yet there is evidence that gustatory adaptation exists in several primate taxa. One is the distally feathered tongues observed in non-destructive nectar feeders, such as Eulemur rubriventer. We compare both the macro and micro anatomy of three lemurid species who died of natural causes in captivity. We included the following two non-destructive nectar feeders: Varecia variegata and Eulemur macaco, and the following destructive flower feeder: Lemur catta. Strepsirrhines and tarsiers are unique among primates, because they possess a sublingua, which is an anatomical structure that is located below the tongue. We include a microanatomical description of both the tongue and sublingua, which were accomplished using hematoxylin–eosin and Masson trichrome stains, and scanning electron microscopy. We found differences in the size, shape, and distribution of fungiform papillae, and differences in the morphology of conical papillae surrounding the circumvallate ones in all three species. Most notably, large distinct papillae were present at the tip of the tongue in nectar-feeding species. In addition, histological images of the ventro-apical portion of the tongue displayed that it houses an encapsulated structure, but only in Lemur catta case such structure presents cartilage inside. The presence of an encapsulated structure, coupled with the shared morphological traits associated with the sublingua and the tongue tip in Varecia variegata and Eulemur macaco, point to possible feeding adaptations that facilitate non-destructive flower feeding in these two lemurids.

Fatal Hymenolepis nana cestodiasis in a ring-tailed lemur (Lemur catta)

The cestode Hymenolepis nana is a common parasite of humans and mice. Fecal shedding in the absence of clinical disease has previously been reported in ring-tailed lemurs ( Lemur catta). This report describes fatal, disseminated H. nana cestodiasis infection in an aged ring-tailed lemur in a zoological collection. The parasites were associated with severe multifocal to coalescing and regionally extensive pyogranulomatous hepatitis and moderate multifocal pneumonia. The morphology of the parasites was highly unusual. Profiles were variably sized, ellipsoid to irregularly serpiginous, lined by a thin tegument, and filled with lightly eosinophilic fibrillar stroma and numerous, round basophilic cells. Polymerase chain reaction targeting a portion of the 18S rRNA gene and DNA sequencing of the amplicon showed 100% homology with H. nana.

Visitors’ Attitudes Toward Non-Human Primates in a Free-Roaming Multi-Species Sanctuary (Monkeyland, South Africa)

The aim of the present study is to investigate themes related to visitors’ perceptions of captive wildlife in particular, attitudes towards non-human primates (henceforth, primates). This research took place in free-roaming, multi-species primate sanctuary, Monkeyland (South Africa), where 400 visitors were interviewed using an anonymous survey both before and after attending a guided tour. The answers were divided into different categories, in order to standardize the motivations behind tourists’ choices. The results of the survey demonstrated that most visitors agree that a primate would not be a good companion animal. Visitors’ desire to touch primates was found to be positively correlated with desire for companion primates and inversely associated with visitor age. In response to: “would you like to touch a monkey?”, the majority of tourists who expressed this desire seemed aware that such interactions are not appropriate, with concern for animal welfare and human health. Of the various primate species present in the sanctuary, visitors preferred the ring-tailed lemur (Lemur catta) and, generally speaking, expressed appreciation for primates’ “cuteness”. Our results indicate a general awareness by the visitors on the importance of animal welfare in the human interactions with captive wildlife, in agreement with the “hands-off” policy of Monkeyland primate sanctuary. We discuss the findings from a general to zooanthropological point of view, proposing some reflections on the attitudes of visitors toward non-human primates.

Zoo Visitor Attitudes Are More Influenced by Animal Behaviour than Environmental Enrichment Appearance

Decisions on environmental enrichment programmes are sometimes based on the assumption that non-natural or artificial looking items negatively affect visitor experiences. In this study, we developed a questionnaire to assess zoo visitor attitudes towards enrichment appearance in an outdoor walk-through enclosure for ring-tailed lemurs (Lemur catta). Naturalistic and artificial looking enrichment items were alternately provided in the enclosure. A total of 371 visitors filled out the questionnaire: 174 in the naturalistic and 197 in the artificial conditions. Both researchers and visitors conducted behavioural observations of the lemurs. Our results suggest that the appearance of the items did not have an effect on visitor attitudes and that visitors recognised both naturalistic and artificial items as enriching for the animals. Moreover, the behaviour and visibility of the lemurs had a greater effect on the visitors’ attitudes. We suggest that during the design of enrichment items, less concern should be placed on the appearance of the items and more on their effect on animal behaviour. Ultimately, this would improve both animal welfare in captivity and the visitor experience.

Gut microbiota of ring-tailed lemurs (Lemur catta) vary across natural and captive populations and correlate with environmental microbiota

Background: Inter-population variation in host-associated microbiota reflects differences in the hosts' environments, but this characterization is typically based on studies comparing few populations. The diversity of natural habitats and captivity conditions occupied by any given host species has not been captured in these comparisons. Moreover, intraspecific variation in gut microbiota, generally attributed to diet, may also stem from differential acquisition of environmental microbes - an understudied mechanism by which host microbiomes are directly shaped by environmental microbes. To more comprehensively characterize gut microbiota in an ecologically flexible host, the ring-tailed lemur (Lemur catta; n = 209), while also investigating the role of environmental acquisition, we used 16S rRNA sequencing of lemur gut and soil microbiota sampled from up to 13 settings, eight in the wilderness of Madagascar and five in captivity in Madagascar or the U.S. Based on matched fecal and soil samples, we used source-sink ecological theory to examine covariation between the two types of consortia. Results: The diversity of lemur gut microbes varied markedly within and between settings. Microbial diversity was not consistently greater in wild than in captive lemurs, indicating that this metric is not necessarily an indicator of host habitat or condition. Variation in microbial composition was inconsistent with either a single, representative gut community for wild conspecifics or a universal 'signal of captivity' that homogenizes the gut consortia of captive animals. Despite the similar, commercial diets of captive lemurs on both continents, lemurs within Madagascar were compositionally most similar, suggesting that non-dietary factors govern some of the variability. In particular, soil microbial communities were most distinct between the two continents, and there was significant and context-specific covariation between lemur gut and soil microbiota. Conclusions: As one of the broadest, single-species investigations of primate microbiota, our study highlights that gut consortia are sensitive to multiple scales of environmental differences. This finding begs a reevaluation of the simple 'captive vs. wild' dichotomy. Beyond the important implications for animal care, health, and conservation, our finding that environmental acquisition may mediate aspects of host-associated consortia further expands the framework for how host-associated and environmental microbes interact across different microbial landscapes.

Effects of Enclosure and Environmental Enrichment on the Behaviour of Ring-Tailed Lemurs (Lemur catta)

Environmental enrichment is widely used to improve the quality of life of animals under human care. To successfully implement enrichment programs, it is important to evaluate their effect in different enclosure types since housing conditions may change depending on external factors, such as husbandry, management, or seasonal variation. This study investigates how ring-tailed lemur (Lemur catta) behaviour changes with the availability of enrichment items and the type of enclosure the animals are housed in. Through observations, we compared the behaviour of the lemurs in an indoor and outdoor enclosure, both without and with enrichment items. Although we observed enrichment effects, we found that enclosure type had a bigger effect on the lemurs’ behaviour. Additionally, behavioural changes induced by enrichment items differed between indoor and outdoor enclosures. These results indicate that the effectiveness of enrichment items may depend on the enclosure in which they are provided and consequently suggest that the impact of these programs should not be generalised over enclosure types. This highlights that the evaluation of environmental enrichment programs remains important when optimising zoo animal welfare.