Severe dental wear and tooth loss is often assumed to impede the processing, breakdown, and energetic conversion of food items, thereby negatively impacting individual health, reproduction, and survival. Ring-tailed lemurs at the Beza Mahafaly Special Reserve demonstrate exceptionally high frequencies of severe dental wear and antemortem tooth loss, yet often survive multiple years with these impairments. To test the hypothesis that these lemurs mitigate tooth loss through behavioral adjustments, we collected 191 h of observational data from 16 focal subjects, eight without tooth loss and eight with between 3% and 44% loss. These data indicate dentally-impaired ring-tailed lemurs show compensatory behaviors consistent with the demands of living in a social group. During early afternoon (12:00-14:30 h) individuals with loss showed trends towards higher frequencies of foraging and grooming, while individuals without loss rested significantly more often. Individuals with >10% loss (n = 7) showed higher frequencies of feeding, foraging, and grooming, and lower frequencies of resting during this period than individuals with <10% loss (n = 9). Individuals with tooth loss maintained relatively higher levels of feeding and foraging throughout the day. These individuals licked tamarind fruit at higher frequencies, likely spending more time softening it before ingestion. These individuals did not demonstrate longer feeding bouts overall, although bouts involving tamarinds were significantly longer. Individuals with marked toothcomb wear engaged in higher rates of certain types of allogrooming, demonstrating that social behaviors are used to compensate for reduced grooming efficiency. These data have implications for interpreting behavioral responses to dental impairment in the fossil record.

During mastication, foods are reduced into particles suitable for swallowing and digestion. Smaller particles possess a greater surface area per unit of volume on which digestive enzymes and bacteria may work than relatively larger particles, and are thus more readily digested. As dental morphology facilitates the breakdown of diets with specific mechanical properties, extensive dental wear and/or tooth loss may impede an individual's ability to break down and exploit foods. We present data demonstrating a relationship between dental impairment and particle size in 43 fecal samples from 33 ring-tailed lemurs at the Beza Mahafaly Special Reserve (BMSR), Madagascar. All fecal samples were sifted through three sieves of decreasing size (11.2 mm, 4.75 mm, and 1.0 mm). The resulting fraction in each sieve was then weighed and assessed in relation to individual dental impairment status. With increasing wear, the percentage of each sample within the 1.0 mm sieve decreases, whereas that in the 11.2 mm sieve increases with increasing postcanine wear, although these effects are not present when limited to individuals without tooth loss. Individuals with tooth loss also demonstrate larger proportions of fecal material 1.0-4.75 mm in size. Dental impairment results in larger food particles and potentially less efficient utilization of foods. When fecal material was examined by leaf vs. fruit content, individuals with tooth loss demonstrated reduced proportions of fruit in the 1.0 mm and 11.2 mm sieves. These data suggest individuals with tooth loss consume less fruit than those without loss, potentially reflecting a reduced ability to process tamarind fruit, a key fallback resource at BMSR.

Coat and body mass status provide a potential noninvasive way to assess primate health status as well as the effects of seasonality, resource use and reproductive state. Coat and body condition were scored visually for 36 wild Lemur catta at the Bezà Mahafaly Special Reserve, Madagascar, from July 2012 to March 2013. Coat quality generally increased during the wet season when resource availability increased, in contrast to that observed during the resource-depleted dry season. Alopecia frequency increased from June to December and declined between January and March. Sex differences for coat condition were only observed in January, when males had superior coat scores. Body condition did not vary by month or sex except in February, when males were larger than females. Females that birthed infants were of lower body size than individuals who did not for November and from January to March. Our results indicate visual methods effectively detect variability in coat and body condition related to seasonality and reproductive status. Such methods present a noninvasive means for assessing the impact of seasonal resource availability, stresses of infant care and reproductive state on ring-tailed lemurs, and may be useful for assessing the impacts of these factors on general health status.

Soft tissue injuries are rarely reported in wild primates as these heal fast, are not obvious, and are rapidly scavenged or decompose after death. An adult female ring -tailed lemur (Lemur catta) was found to have a chronic gastrointestinal fistula in Beza Mahafaly Special Reserve, Madagascar. She was observed monthly for 13 months until her remains, which showed evidence of dog predation, were found. Until then, she was in good body condition, had gained weight from the previous year and was observed to exhibit normal behaviour and produce an infant. This report documents a wild strepsirrhine primate able to survive significant soft tissue injury in an anthropogenically disturbed habitat.

As global non-human primate populations show dramatic declines due to climate change, land transformation and other anthropogenic stressors, it has become imperative to study physiological responses to environmental change in order to understand primate adaptability and enhance species conservation strategies. We examined the effects of seasonality on faecal glucocorticoid metabolite (fGCM) concentrations of free-ranging male and female thick-tailed greater galagos (Otolemur crassicaudatus) in an Afromontane habitat. To do so, we established an enzyme immunoassay (EIA) for monitoring fGCM concentrations in the species using a biological validation. Following this, faecal samples were collected each month over the course of a year from free-ranging males and females situated in the Soutpansberg Mountains, Limpopo, South Africa. Multivariate analyses revealed lactation period was a driver of fGCM levels, whereas sex and food availability mostly influenced seasonal fGCM concentrations in the total population. Thus far, the results of this study show that drivers of fGCM levels, an indication of increased adrenocortical activity, in O. crassicaudatus are numerous and complex within the natural environment. The species may be adapted to such conditions and an extreme change to any one component may result in elevated fGCM levels. This increases our understanding of strepsirrhine primate physiology and offers initial insights into species adaptability to a challenging environment.