The effects of hibernation on the time of coagulation of the American bullfrog, Rana catesbeiana

Cold conditions during winter months greatly reduce heart rate in ectothermic animals, such as bullfrogs, resulting in slow, intermittent blood flow. Slow or intermittent flow of blood often results in coagulation, yet the blood of these ectotherms fails to coagulate. In this study, the effects of the stages of hibernation from the onset of temperature decline, through the duration of constant low temperature exposure, was studied by observing the time of blood coagulation of American bullfrogs (Rana catesbeiana) using activated partial thromboplastin time (aPTT). It was found that the time of coagulation increased incrementally along with the decreasing temperature of the hibernation environment. These results suggest that there is a trend between a decrease in temperature and time of coagulation