Zweifel Mar. 31, 1951 269 Pana boglii Observations on captive Rana from Shasta and Contra Costa Country Calling The call is a short saeping affair which sounds just about like "croak". The croak is given by both males and females. The males call whenever attempting to amplex (?) when another frog attempts to amplex with them, or sometimes without tactile stimulus. The large female from Contra Costa Co. croaks whenever a male attempts to amplex her. She appears rather thin and has probably already laid her eggs. Perhaps croaking serves to inform a would-be amplexer that the object of his attention is unavailable, either by reason of being male or already having laid eggs. By simulating amplexus, it was possible to get both a male and a female croaking at the same time. The croak of the female is about one full tone below that of the male, is given more slowly, and is less saeping. The throat distention of the male is notably greater. Throat color On the light phase, the throat of the Contra Costa frog is almost immaculate white with only a little darkening around the.