A more detailed seasonal division of the energy balance and the protein balance of Japanese macaques (Macaca fuscata) on Kinkazan Island, northern Japan

Y. Tsuji, N. Kazahari, M. Kitahara, S. Takatsuki

Nakagawa (Am J Primatol 41:267–288, 1997) reported that both the　gross energy and gross protein intakes of an adult female Japanese macaque (Macaca fuscata) on Kinkazan Island, northern Japan, were high in spring (March–May) and fall (September–November) and low in summer (June–August) and winter (December– February), and that these values reflected the seasonal differences in nutritional conditions (defined as whether the intakes of energy and protein satisfy the requirements). We estimated the energy balance (energy intake minus its expenditure) and the protein balance (protein intake minus its requirement) of the monkeys on Kinkazan Island every month over the course of 1 year (2004–2005) in order to verify Nakagawa’s conclusions. Like Nakagawa, we found that the energy balance of the monkeys in the fall was higher than in the summer and winter, whereas the protein balance in the fall was higher than in the winter. However, we did not find that spring energy and protein values were greater than summer and winter values. We also did not find that summer protein values were low. Both the energy balance and the protein balance changed rapidly within the same season. The energy intakes and the energy balances were higher in mid-spring and mid- and late fall and lower in late spring and early summer, whereas the protein intakes and the protein balances were higher in mid-spring and mid-summer and lower in early and mid-winter. Since Japanese macaques respond to seasonal changes in food supply by changing their foods, continuous data collection with short intervals is recommended in order to accurately document the energy and protein balances of the monkeys.

Primates 49, 2, 157-160, 2008

　宮城県金華山島で、ニホンザル (Macaca fuscata) 成獣メスのエネルギー摂取量とタンパク質摂取量、およびエネルギーバランス（摂取量―要求量）とタンパク質バランスを2004年から2005年にかけて調べ、得られた結果を先行研究(Nakagawa,1997) の結果と比較した。先行研究と同様、秋のエネルギーバランスは夏や冬に比べて高く、また秋のタンパク質バランスは冬に比べて高かったので、秋の栄養状態は良好だと判断された。しかし、春のエネルギーバランスやタンパク質バランスが従来言われていたよりも低いこと、夏のタンパク質バランスが比較的高いことなど、先行研究とは異なる結果も得られた。ニホンザルの生息する温帯では食物環境は短い周期で変化する。ニホンザルの食性もそれに応じて変化すると考えられるので、ニホンザルの栄養状態を評価するに当たっては、短期のスパンで調査を行うことが重要である。

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