title: Primate Resting Postures: Constraints by Foregut Fermentation?
abstract: Although resting is one of the dominant behaviors of foregut-fermenting primates (i.e., colobines), their resting posture has rarely received attention. We hypothesize that colobines are more constrained in their resting position than hindgut-fermenting primates and that colobines assume a sitting resting position for specific reasons. To test this hypothesis, we followed two approaches. First, we observed resting positions in two captive individuals each of eight species and tested whether colobines rested in a sitting position more than other primates. Second, we collected literature data on free-ranging specimens of 31 species and again tested whether colobines rested in a sitting position more than other primates. Both approaches indicated that colobines spent more time in a sitting posture than other primates (73.0% vs. 23.2% in captivity and 83.0% vs. 60.9% in the wild, respectively). We hypothesize that the position of the digestive chamber and the necessity of frequently having to eructate digestion gases force colobines to take a sitting posture to avoid pressure on the thorax and respiratory organs.
authors.forename: Ikki
authors.initials: I
authors.lastname: Matsuda
authors.forename: Colin A
authors.initials: CA
authors.lastname: Chapman
authors.forename: Chua Ying
authors.initials: CY
authors.lastname: Shi Physilia
authors.forename: John Chih
authors.initials: JC
authors.lastname: Mun Sha
authors.forename: Marcus
authors.initials: M
authors.lastname: Clauss
mesh_terms: D000818:Animals; D000835:Animals, Wild; D000836:Animals, Zoo; D004063:Digestion / Q000502:physiology*; D005285:Fermentation; D011187:Posture / Q000502:physiology*; D011323:Primates / Q000145:classification / Q000502:physiology*; D012146:Rest / Q000502:physiology*; D013045:Species Specificity
keywords: colobine; foregut fermenter; hindgut fermenter; positional behavior; sitting; sloths