Nocturnal behavior by a diurnal ape, the West African chimpanzee ( Pan troglodytes verus ), in a savanna environment at Fongoli, Senegal

Bibliographic Data

ID8316702
AuthorsJill D Pruetz (0000-0002-9151-8571, Department of Anthropology Texas State University San Marcos Texas 78666, corresponding author)
Year2018
Volume166
Issue3
Pages541-548
Publication date2018-07-01
Peer ReviewedYes
Open AccessYes
TypeARTICLE
VenueAmerican Journal of Physical Anthropology (JOURNAL)
Journal identifiersISSN: 0002-9483 • E-ISSN: 1096-8644
PublisherWiley (PUBLISHER • GB)
DOI10.1002/ajpa.23434
PMID29417991
OpenAlexW2790145895
LanguageEN
Citations received21
References cited47

OBJECTIVES: I report on the nocturnal behavior of Fongoli chimpanzees in a savanna mosaic during different seasons and lunar phases and test the hypothesis that hot daytime temperatures influence activity at night. I predicted that apes would be more active at night during periods of greater lunar illuminosity given diurnal primates' lack of visual specializations for low-light conditions and in dry season months when water scarcity exacerbated heat stress. MATERIALS AND METHODS: I observed chimpanzees for 403 hrs on 40 nights between 2007 and 2013 and categorized their activity as social, movement, or vocalization. I scored their activity as occurring after moonrise or before moonset and considered the influence of moon phase (fuller versus darker phases) as well as season on chimpanzee nocturnal behavior in the analyses. RESULTS: Results indicate that apes were more active after moonrise or before moonset during fuller moon phases in the dry season but not the wet season. Most night-time activity involved movement (travel or forage), followed by social behavior, and long-distance vocal communication. DISCUSSION: Animals in highly seasonal habitats often exhibit thermoregulatory adaptations but, like other primates, chimpanzees lack physiological mechanisms to combat thermal stress. This study provides evidence that they may exhibit behaviors that allow them to avoid high temperatures in a savanna environment, such as feeding and socializing at night during the hottest time of year and in the brightest moon phases. The results support theories invoking thermal stress as a selective pressure for hominins in open environments where heat would constrain temporal foraging niches, and suggest an adaptability of sleeping patterns in response to external factors

Biology · Cercopithecus aethiops · Dry season · Forage · Foraging · Full moon · Geography · Habitat · Nocturnal · Troglodytes · Wet season · Zoology · Ecology · Paranormal Experiences and Beliefs · Pleistocene-Era Hominins and Archaeology · Primate Behavior and Ecology

Tools

Open DOISci-Hub