Extreme Starvation Impacts Organ Size and Water Content But Not Bone Integrity in Rattlesnakes

Ambush-hunting snakes have long been of interest in the biology of fasting and starvation, as they are adapted to withstand long durations without eating. Ethical experimental constraints have limited our understanding of their limits in these abilities. The confiscation of over 50 Western Rattlesnakes (Crotalus oreganus) by the California Department of Fish and Wildlife from an animal hoarder who had neglected them allowed us to examine the carcasses for effects of extreme starvation. Some of these snakes were extremely starved, being one-third to one-half of the weight of wild snakes of the same length. We used dissection to determine the effects of starvation on the mass of hearts, livers, kidneys, gallbladders, testes, and fat bodies. We desiccated hearts, livers, and kidneys to investigate tissue water content in those organs. We used nanoindentation and photo analysis of bone cross sections to assess whether starvation had any impact on bone integrity. We demonstrated that all measured visceral organs shrank dramatically in response to starvation, with the exception of the gallbladder, which showed the opposite response. We also found that female rattlesnakes tended to have larger livers and gallbladders than males. The tissue water content of the liver and kidneys increased with the extent of starvation, and that of the heart appeared to be unaffected. We found no evidence for changes in rattlesnake bone integrity in response to starvation, but more testing is needed. These results provide insight into how one of the most fasting-adapted species of vertebrate responds to extreme starvation.