Specialized use of two fingers in free-ranging aye-ayes (Daubentonia madagascariensis)

• Published in: American journal of primatology Vol. 70; no. 8; pp. 786 - 795
• Main Authors: Lhota, Stanislav, Jůnek, Tomáš, Bartoš, Luděk, Kuběna, Aleš A.
• Format: Journal Article
• Language: English
• Published: Hoboken Wiley Subscription Services, Inc., A Wiley Company 01.08.2008
• Subjects: Animals; Daubentonia madagascariensis; digits; extractive foraging; Feeding; Feeding Behavior; Female; Fingers; Functional Laterality; hand; lemurs; Madagascar; Male; National parks; Primate behaviour; Primate biology; Primatology; Strepsirhini - physiology
• ISSN: 0275-2565; 1098-2345
• DOI: 10.1002/ajp.20548

The aye‐aye (Daubentonia madagascariensis) possesses a highly specialized hand with two fingers, the third and the fourth, being used in a way unparalleled by any other primate. We observed the use of the third and the fourth fingers in various activities in four free‐ranging aye‐ayes. We found that the thin third finger was used exclusively or preferably for tapping, inserting into the mouth (probably for cleaning the teeth) and probing for nectar, kernels and insects in bamboo, twigs and live wood. In contrast, the robust fourth finger was used preferably when eating jackfruit (Artocarpus heterophyllus). When probing for invertebrates in soft plant tissues and in dead wood, both fingers were used in high proportions. To extract the contents from coconuts, the two fingers were apparently used for different tasks. From this small (686 observations), but unique, study of free‐ranging aye‐ayes, we conclude that the third finger appears to be specialized for use in tasks requiring high mobility, sensitivity and precision, whereas the fourth finger appears to be specialized for tasks requiring strength, scooping action and deep access. Am. J. Primatol. 70:786–795, 2008. © 2008 Wiley‐Liss, Inc.