著者

IWANO Taizo

出版者

The Center for African Area Studies, Kyoto University

雑誌

African Study Monographs (ISSN:02851601)

巻号頁・発行日

vol.12, no.1, pp.19-42, 1991-06

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This report forms one of a series of papers examining my hypothesis that the aye-aye's (Daubentonia madagascariensis) unusual adaptation is more reasonably explained by a diet of hard-nuts rather than one of wood-boring insect larvae. An extensive survey showed that the distribution of the aye-aye and that of Canarium spp. (which bears hard-nuts) overlapped on the eastern coast and in the central highland of Madagascar. An intensive study was conducted at the Nosy Mangabe Special Reserve on a total of 33 nights during three different periods in 1988 and 1989. I observed the aye-ayes eating ramy nuts (Canarium spp.) throughout the entire observation period, the parasitical outgrowth of the cambial layer of Afzelia bijuga from June through October except for August, insect larvae, beans of Entada phaseoloides, and the flowers of Macaranga cuspidata from September to October. The aye-aye spends a relatively high proportion (over 40%) of its time engaged in feeding during October and December when ramy forms the main part of its diet, while from June to July, and September, when other food items are additionally consumed, the proportion of resting time becomes relatively high (over 10%). Although the aye-aye was often spotted singly, it was also common to see more than one individual (up to four) adjacent to another (13% of all the observation units in which the aye-aye was spotted) throughout the observation periods. Two species of ramy (Canarium spp.) are distributed in the Nosy Mangabe Special Reserve. C. Boivini bore fruits over the entire observation period. A single nut of the ramy provides of 4.38 kcal of energy and requires about two minutes on average for consumption. I estimated the nightly energy intake as 262.8 kcal.