Complete physical examinations and biomedical sample collection were performed on 70 free-ranging ring-tailed lemurs (Lemur catta) from three different habitats in the Beza Mahfaly Special Reserve (BMSR), in southern Madagascar, to assess the impact of humans and habitat on lemur health. Lemurs were chemically immobilized with ketamine and diazepam administered via blow darts for concurrent biomedical, morphometric, and behavioral studies. Subsets of the animals had blood analyzed for hematology, serum chemistry, micronutrients, fat-soluble vitamins (vitamins A, D, and E), measures of iron metabolism, and polymerase chain reaction assays (PCR) for Toxoplasma gondii, Hemoplasma spp., Bartonella spp., Ehrlichia spp., Anaplasma phagocytophilum, and Neorickettsia risticii. Results were compared on the basis of gender and the habitats at the study site: reserve (intact gallery forest), degraded (human inhabited and altered), and marginal (dry didieracea forest with heavy grazing and tree cutting). Levels of vitamin D, triglycerides, and cholesterol, and measures of iron metabolism for BMSR lemurs were greater than those previously reported for a free-ranging lemur population (Tsimanampetsotsa Strict Nature Reserve, Madagascar) with less access to foods of anthropogenic origin. BMSR ring-tailed lemurs from a habitat with less water (marginal) had higher sodium (P = 0.051), chloride (P = 0.045), osmolality (P = 0.010), and amylase (P = 0.05) levels than lemurs from other BMSR habitats, suggesting that these lemurs were less hydrated. Vitamin D levels of male lemurs were higher (P = 0.011) than those of females at BMSR, possibly because of differences in sunning behavior or differential selection of food items. The biological significance is uncertain for other parameters with statistically significant differences. All samples tested (n = 20) were negative for the pathogens tested using PCR assays. Continued concurrent biomedical and ecological research is needed at BMSR to confirm these results and determine their association with population mortality and fecundity rates.
Ring-tailed lemurs live in a range of habitats in southwestern Madagascar. To date, much of the knowledge of ring-tailed lemur ecology, biology and behavior come from riverine gallery forests sites. Recent years have seen an expansion of comprehensive research on this resilient species, including areas of limestone spiny forest along Madagascar's southwestern coast. This work is documenting newly discovered behaviors by this species. The regular use of cliff-faces and embedded crevices and caves by ring-tailed lemurs in southwestern Madagascar are reported here. Cave use by several anthropoid primates has been explained as a thermoregulatory behavior. It is suggested that cliff-face and cave use by these ring-tailed lemurs serves several purposes, including resource acquisition, thermoregulation, and as an anti-predator avoidance strategy in the absence of suitable large sleeping trees. Observations indicate that the limestone boundaries of the Mahafaly Plateau and their associated xerophytic scrub forests warrant further conservation attention, given the presence of behavioral variation and increasing threats to this endangered primate species. RÉSUMÉ Lemur catta occupe divers habitats dans le Sud-ouest de Madagascar. L'écologie, la biologie et le comportement de Lemur catta sont actuellement mieux connus des populations vivant dans les forêts riveraines et les zones environnantes. Pour mieux comprendre cette espèce de lémurien, les recherches ont été étendues à d'autres habitats dont les forêts épineuses du plateau calcaire qui est situé le long du littoral Sud-ouest de Madagascar. Dans cette étude nous rapportons les comportements récemment découverts de Lemur catta qui utilise les falaises et les grottes dans le Sud-ouest de Madagascar. L'utilisation des grottes par la plupart des primates hominoïdes est liée à un avantage thermorégulateur offert par ce milieu. Dans notre cas, l'exploitation de falaises et de grottes par Lemur catta semble être associée à un mécanisme permettant d'échapper aux prédateurs et à l'absence de grands arbres qui devaient servir de dortoirs. De sorte que les falaises et les forêts épineuses du plateau calcaire Mahafaly ont besoin d'une conservation particulière car nos résultats de suivis montrent que les changements de comportement du lémurien emblématique de cette région trouve vraisemblablement son origine dans la dégradation de l'environnement de cette espèce.
Coprophagy occurs in a number of animal species, including nonhuman primates. During the 2003-2004 dry seasons at the Beza Mahafaly Special Reserve, Madagascar, we observed wild ring-tailed lemurs (Lemur catta) consuming dried fecal matter from three different species. Ring-tailed lemurs consumed human feces on 12 occasions, cattle feces twice, and feral dog feces once. Coprophagy in this population may be a behavioral adaptation that provides animals access to energy and nutrients and may be an important nutritional source for older, and/or dentally impaired individuals during the dry season.
Habitat disturbances may impact behaviors of animals, including their activity patterns. In southwestern Madagascar, timing of gray-brown mouse lemur activities was investigated in adjacent forests with different levels of human disturbance. Mouse lemurs were encountered more frequently during the second part of the night in the unfenced, more disturbed forest than in the fenced, less-disturbed forest. The extension of mouse lemur activity period in the unfenced forest may be due to differences in forest composition resulting in higher travel costs or a loss of canopy cover which may limit their use of torpor. RÉSUMÉ Les perturbations de l'habitat peuvent avoir un impact sur le comportement des animaux, y compris sur leur rythme d'activité. Le déroulement des activités des microcèbes a été étudié dans des forêts adjacentes du Sud-ouest de Madagascar. Une de ces forêts a été protégée du pâturage par une clôture tandis que l'autre ne profitait pas d'un tel dispositif en étant ainsi nettement exploitée par l'Homme et son bétail. Les microcèbes ont été rencontrés plus fréquemment au cours de la deuxième partie de la nuit dans la forêt non clôturée que dans la forêt clôturée. Bien que cette étude n'ait pas permis de détecter des différences dans la disponibilité des insectes ou des fruits, des évaluations plus détaillées de la composition des espèces d'arbres et l'abondance des insectes sont nécessaires pour déterminer l'impact de la qualité nutritionnelle ou de la distribution des ressources sur les rythmes d'activité des microcèbes dans la forêt non clôturée. D'un autre côté, l'allongement de la période d'activité des microcèbes dans la forêt non clôturée peut être lié à une perte de la couverture de la canopée, elle-même à l'origine d'une élévation des températures diurnes dans la forêt non clôturée qui réduirait la durée pendant laquelle les microcèbes pourraient être en torpeur dans cette forêt.
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