A comparison of salivary pH in sympatric wild lemurs (Lemur catta and Propithecus verreauxi) at Beza Mahafaly Special Reserve, Madagascar

Abstract

Chemical deterioration of teeth is common among modern humans, and has been suggested for some extinct primates. Dental erosion caused by acidic foods may also obscure microwear signals of mechanical food properties. Ring-tailed lemurs at the Beza Mahafaly Special Reserve (BMSR), Madagascar, display frequent severe tooth wear and subsequent tooth loss. In contrast, sympatric Verreaux's sifaka display far less tooth wear and infrequent tooth loss, despite both species regularly consuming acidic tamarind fruit. We investigated the potential impact of dietary acidity on tooth wear, collecting data on salivary pH from both species, as well as salivary pH from ring-tailed lemurs at Tsimanampesotse National Park, Madagascar. We also collected salivary pH data from ring-tailed lemurs at the Indianapolis Zoo, none of which had eaten for at least 12 hr before data collection. Mean salivary pH for the BMSR ring-tailed lemurs (8.098, n=41, SD=0.550) was significantly more alkaline than Verreaux's sifaka (7.481, n=26, SD=0.458). The mean salivary pH of BMSR (8.098) and Tsimanampesotse (8.080, n=25, SD=0.746) ring-tailed lemurs did not differ significantly. Salivary pH for the Indianapolis Zoo sample (8.125, n=16, SD=0.289) did not differ significantly from either the BMSR or Tsimanampesotse ring-tailed lemurs, but was significantly more alkaline than the BMSR Verreaux's sifaka sample. Regardless of the time between feeding and collection of pH data (from several minutes to nearly 1 hr), salivary pH for each wild lemur was above the "critical" pH of 5.5, below which enamel demineralization occurs. Thus, the high pH of lemur saliva suggests a strong buffering capacity, indicating the impact of acidic foods on dental wear is short-lived, likely having a limited effect. However, tannins in tamarind fruit may increase friction between teeth, thereby increasing attrition and wear in lemurs. These data also suggest that salivary pH varies between lemur species, corresponding to broad dietary categories.

Variation in dental wear and tooth loss among known‐aged, older ring‐tailed lemurs (Lemur catta): a comparison between wild and captive individuals

“…Among the maxillary teeth, left and right P3 through M1 show significantly greater wear at BMSR. These three tooth positions are frequently lost owing to excessive wear at BMSR, a pattern associated with processing mechanically and physically challenging foods, specifically fruit of the tamarind tree (T. indica), an important fallback food among ring-tailed lemurs inhabiting several riverine gallery forests of southern Madagascar [e.g., Cuozzo & Sauther, 2004, 2006aCuozzo et al, 2008;Gemmill & Gould, 2008;Mertl-Millhollen et al, 2006;. Among the mandibular teeth, all tooth comb positions at BMSR show significantly more wear than in the captive sample.…”

“…Long-term study of this population has documented a series of dental health patterns [Cuozzo & Sauther, 2004, 2006aCuozzo et al, 2008;Sauther et al, 2002Sauther et al, , 2006, including a high frequency of severe tooth wear and antemortem tooth loss. Beginning in 2003, F. P. C. and M. L. S. initiated a systematic study of the dentition of this lemur population, in part to identify the proximate causes of this phenomenon [e.g., Cuozzo & Sauther, 2004, 2006aCuozzo et al, 2008;. At BMSR, more than 20% of all individuals studied have lost at least one tooth.…”

“…The vast majority have been lost owing to excessive wear rather than disease or other pathology [Cuozzo & Sauther, 2004, 2006b, with several individuals having lost more than 80% of their teeth [Cuozzo & Sauther, 2006b;Sauther et al, 2002]. In addition, the pattern of wear and subsequent tooth loss shows a strong relationship with the teeth used to process tamarind fruit (Tamarindus indica), a mechanically challenging food [e.g., Yamashita, 2008], and an important fallback resource of BMSR gallery forest ring-tailed lemurs [Cuozzo & Sauther, 2006b;Cuozzo et al, 2008;. Although the pattern of severe wear and loss is wellknown for the BMSR population, with dramatic increases in tooth loss sometimes occurring within as little as 1 year [Cuozzo & Sauther, 2006b], we have yet to explore this issue in the context of longevity and advanced age.…”

“…Also, we explore the potential relationship between behavior, ecology, and tooth wear in these individuals, thereby providing rare data to assess the assumed connections between tooth wear and aging within a wild primate population. Given the rarity of wild lemur (and other primate) populations with known-aged older individuals, in 2005 we initiated the longitudinal study of a captive population of ringtailed lemurs at the Indianapolis Zoo [e.g., Cuozzo et al, 2008;] to provide a broader interpretive context for our work in Madagascar. Specifically, we integrated the study of these captive, known-aged lemurs, with controlled diets, annual medical evaluations, dental cleanings, and no predation, to provide a comparative template of patterns of dental wear one might expect in an ''optimal'' population.…”

Condensed Tannin Intake in Spiny-Forest-Dwelling Lemur catta at Berenty Reserve, Madagascar, during Reproductive Periods

“…Conversely in a study at Beza Mahafaly Special Reserve, Yamashita [2008] found only negligible amounts of tannins (1/135 assays) in gallery and deciduous forest plant foods consumed by ring-tailed lemurs at this site over a 13-month period. However, the fruit and leaves of Tamarindus indica, an extremely important food resource and fallback food for L. catta in gallery forests [Sauther, 1993[Sauther, , 1998Yamashita, 2002;Simmen et al, 2006b;Sauther and Cuozzo, in press] contain relatively high tannin concentrations [Watt and Breyer-Brandwijk, 1962;Simmen et al, 2003], and Cuozzo et al [2008] suggest that dietary tannins from tamarind fruit might be a contributing factor to a high frequency of severe tooth wear and tooth loss found in a large sample of L. catta examined at Beza Mahafaly Special Reserve.…”