ANNUAL CYCLE IN LIVER WEIGHT OF MARSH FROG RANA RIDIBUNDA PALLAS, 1771

Abstract

The dry weight of the liver of Rana ridibunda was expressed as percentage of the dry
weight of the body. The female liver weight always exceeds that of the male, except in July
and September. The difference between males and females for the whole year, regardless of
months, was not significant. Livers of both sexes were relatively large prior to hibernation
(December), decreased during hibernation (January and February) until a minimum weight in
March (post-hibernation).
The increase of liver weight during December is apparently simply to meet the metabolic
requirements for survival during hibernation. The percent reduction in liver weight during
hibernation was 1.081% in males and 1.356% in females. The decrease in liver weight during
the hibernation months may be attributed to the utilization of liver glycogen. The rise in mean
weight from August to October indicates that marsh frogs, after spawning, were actively
feeding.