Stokkan K A, Mortensen A, Blix A S
Am J Physiol. 1986 Aug;251(2 Pt 2):R264-7. doi: 10.1152/ajpregu.1986.251.2.R264.
Food intake (FI), feeding activity (FA), and body mass (BM) were recorded continuously throughout a 13-mo period in Svalbard rock ptarmigan kept under natural conditions of light and ambient temperature at Svalbard (79 degrees N). FI was persistently high from March until August, including the period when daylight is continuous, whereas it was low from November until January, when it is permanently dark. From August until November, BM doubled, while FI dropped to one-third. BM fell rapidly from mid-November until April despite a doubling of FI from February until March. From August until mid-November and from February until mid-April FA occurred mainly during the light period of the day. From late November until February and from mid-April until August intermittent FA occurred continuously. It is suggested that the seasonal changes in BM are not determined by FI alone but depend heavily on seasonal changes in locomotor activity as reflected in FA.
在斯瓦尔巴群岛（北纬79度）自然光照和环境温度条件下饲养的斯瓦尔巴岩雷鸟，在13个月的时间里持续记录其食物摄入量（FI）、进食活动（FA）和体重（BM）。从3月到8月，包括日照持续的时期，FI一直很高；而从11月到1月，日照永久黑暗时，FI很低。从8月到11月，BM翻倍，而FI降至三分之一。尽管从2月到3月FI翻倍，但从11月中旬到4月BM迅速下降。从8月到11月中旬以及从2月到4月中旬，FA主要发生在白天的光照时段。从11月下旬到2月以及从4月中旬到8月，间歇性FA持续发生。研究表明，BM的季节性变化并非仅由FI决定，而是在很大程度上取决于FA所反映的运动活动的季节性变化。
