The 84th Annual Meeting of the American Association of Physical Anthropologists (2015)


Flowers or figs: Dietary choices in wild white-handed gibbons (Hylobates lar) in western Thailand

LYDIA E.O. LIGHT.

Department of Anthropology, The University of Texas at San Antonio

March 28, 2015 , Gateway Ballroom 2/3/4/5 Add to calendar

Gibbons are often characterized as being highly adapted to feeding on ripe fruit; however, considerable variation exists between gibbon species, between habitats, and in response to seasonal variation. To determine the role of habitat on gibbon diet, I compared the feeding behavior of gibbons occupying distinct habitats in the Huai Kha Khaeng Wildlife Sanctuary. Gibbons here live in both evergreen and mosaic forest areas, which consist primarily of mixed deciduous and deciduous dipterocarp forests where food resources are highly variable in both time and space. I hypothesize that these conditions will result in important differences in gibbon diet between habitats.

Data were collected on four gibbon groups from June 2012-May 2013. Groups living in mosaic forest areas overall ate less fruit (63.4% vs. 72.6%) and insects (4.5% vs. 5.3%) and more leaves (20.7% vs.16.2%), flowers (4.6% vs. 2.7%), and vine shoots (5.8% vs. 1.5%). Seasonal differences in food choice were marked in both habitats. Monthly fruit consumption ranged from 19.7-80.0% (mosaic) and 48.3-95.2% (evergreen). Leaves always comprised at least 5% of the diet for both habitat types, but totaled 57.7% of the mosaic diet in January and 41.6% of the evergreen diet in May. While flowers never comprised more than 10% of the diet in evergreen groups, they contributed 38.1% of the mosaic diet in March. Furthermore, mosaic gibbons were observed consuming bird’s eggs on two occasions in April. These results confirm growing recognition that gibbons are more ecologically flexible than once believed and highlight the importance of intraspecific comparisons.

Funding for this research was provided by IIE Fulbright, National Science Foundation Doctoral Dissertation Improvement Grant (#1154603), American Society of Primatologists, and the UTSA Department of Anthropology.