Hatchling painted turtles (Chrysemys picta) spend their first winter inside natal nests without food and must rely on maternally derived energy in the form of residual yolk for up to nine months. In this study, we take a closer look at the use and movement of residual-yolk energy during the first 33 weeks (~8 mo.) after hatching by measuring changes in mass, lipid content, & protein content of yolk, liver, small intestine, and carcass. Our data showed a significant decrease in yolk mass by 64% and significant increases in carcass & liver masses of 9% & 16%, respectively, during the first 2 weeks after hatching. Yolk mass was further depleted to 17% at week 4, and did not significantly decrease further for the remaining 29 weeks. These results suggest that energy is transferred from residual yolk to somatic storage soon after hatching, and well before hibernation begins. We suggest that a low-temperature-induced down regulation of gut function that renders residual-yolk energy inaccessible during hibernation necessitates digestion and storage of residual-yolk energy soon after hatching when temperatures inside the nest are still high. That strategy may be used despite the net energy cost of digesting, storing, and later mobilizing that residual-yolk-derived energy. We are currently measuring triglyceride & protein contents of the aforementioned body parts to better track the use and movement of energy in the hatchlings
