Sources of variation in fecal cortisol levels in howler monkeys in Belize

Behie, Alison M. and Pavelka, Mary S.M. and Chapman, Colin A. (2010) Sources of variation in fecal cortisol levels in howler monkeys in Belize. American Journal of Primatology, 72 (7). pp. 600-606. ISSN 02752565

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    Abstract

    High cortisol levels are known to cause low fecundity and increased mortality; thus, the prospect of using cortisol as a measure of population health is an exciting one. However, because so many factors can interact to influence cortisol release, it can be difficult to interpret what exactly is creating changes to cortisol levels. This study investigates variation in fecal cortisol levels in a population of black howlers (Alouatta pigra) from 350 fecal samples collected from 33 individuals in more than 4 years. A general linear mixed model revealed that cortisol varied significantly with fruit availability and contact with tourists. When fruit availability was low, cortisol increased, likely because when fruit availability is low monkeys eat less fruit, thus obtaining less sugar. This result may simply reflect cortisol’s metabolic function of mobilizing glucose. It also indicates that these monkeys may be experiencing periods of food stress throughout the year, which was earlier thought to be minimal for a primarily folivorous species. Presence of tourists was the only other factor found to lead to high cortisol; with exposure to tourists increasing stress levels. These results highlight the importance of understanding how physiological factors can influence cortisol, making it easier to interpret results and determine the external social or ecological stressors that may increase cortisol. Am. J. Primatol. 72:600–606, 2010.

    Item Type: Peer-reviewed Journal Article
    Related URLs:
    Unique ID or DOI: 10.1002/ajp.20813
    Publisher: Wiley-Blackwell
    Keywords: Alouatta pigra; howler monkeys; fecal cortisol; ecological stressors; diet; tourism; nutritional stress
    Subjects: (A) Biodiversity > (AG) Mammals > (AGC) Herbivores
    Publication Sources: (3) Other Source > (3D) Other or Unspecified
    Date Deposited: 02 Dec 2010 15:24
    Last Modified: 20 Jan 2011 14:28
    URI: http://eprints.uberibz.org/id/eprint/1077

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