Abstract # 49:

Scheduled for Saturday, September 13, 2014 07:00 PM-09:00 PM: Session 11 (Decatur B) Poster Presentation


D. O. Spence and B. Benefit
New Mexico State University, Department of Anthropology, Breland Hall, Las Cruces, New Mexico 88003, USA
     Hand preference was assessed in a family of siamangs at the El Paso Zoo between September 2013 and March 2014, totaling 45 hours of observation over 18 days. One adult male, one adult female, and their two female offspring (6 and 2 years old) were observed and photographed while foraging for food in the public exhibit. Which hand each individual used in reaching for food, bringing food to the mouth, bug catching, and dipping for drinking water was recorded. The data were used to test for hand preference in each individual and whether handedness differed according to the age and sex of the individual. The adult female was found to exhibit the highest degree of handedness, using her left hand an average of 87.5% of the time for feeding activities, and 100% of the time for bug catching and water dipping. The adult male shows ambidextrous tendencies using either his right or left hand for specific tasks. The juveniles maintain variation, including using feet to bring food to the mouth, and the younger female switching hands during a single behavior but exhibiting a slight left hand preference (62.5%). This study of lateralized behavior in S. syndactylus suggests females may exhibit greater handedness than males, and handedness may not become established until adulthood. Whether handedness is related to female masculinization and/or reflects cerebral specialization is discussed.