AJP - Regulatory, Integrative and Comparative Physiology, Vol 251, Issue 2 264-R267, Copyright © 1986 by American Physiological Society
Food intake, feeding rhythm, and body mass regulation in Svalbard rock ptarmigan
K. A. Stokkan, A. Mortensen and A. S. Blix
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.
