Object manipulation to obtain a food reward in hoolock gibbons, Bunopithecus hoolock

• Published in: Animal behaviour 2006-03, Vol.71 (3), p.621-629
• Main Authors: Cunningham, Clare L., Anderson, James R., Mootnick, Alan R.
• Format: Article
• Language: English
• Subjects: Animal behavior; Animal cognition; Animal ethology; Animal training; Biological and medical sciences; Bunopithecus hoolock; Fundamental and applied biological sciences. Psychology; Mammalia; Monkeys & apes; Psychology. Psychoanalysis. Psychiatry; Vertebrata
• ISSN: 0003-3472; 1095-8282
• DOI: 10.1016/j.anbehav.2005.05.013

Gibbons (family Hylobatidae) have rarely been studied in terms of object manipulation and tool use. We assessed whether hoolock gibbons can learn to pull on a rake-like object to gain a food reward, in a zero-order manipulation task, without specific training. Their learning style was assessed along with their understanding of the tertiary relationships between the rake, a goal object and an environmental feature. Hoolocks used a rake to pull in an out-of-reach food item in less than 90 s on first presentation. The gibbons' behaviour suggests that perceptually restructuring the environment may be within this species' abilities. Their causal understanding of three factors, the rake, the reward and a trap into which the reward could fall and be lost, was moderately better than that of chimpanzees, Pan troglodytes, and capuchins, Cebus spp., on a similar task. Learning of simple associative rules, rather than understanding the physical properties of the trap, might explain the gibbons' performance.