Meeting Abstract

104.3  Sunday, Jan. 6  The effects of day length, hibernation, and hibernaculum temperature on tooth morphology in the Turkish hamster (Mesocricetus brandti) BATAVIA, M; University of California, Berkeley mbatavia@berkeley.edu

Ever-growing rodent incisors deposit dentin – one of the tissues comprising mammalian teeth – on a circadian basis; these daily dentin layers are visible both in histological cross section and on the medial surfaces of incisors. Hibernation disrupts the normal pattern of dentin deposition, and distinct hibernation marks have been documented in the incisor dentin of several rodent species. Little, however, is understood about the factors that influence hibernation mark morphology. We tested the effects of day length, hibernation, and hibernaculum temperature on incisor surface morphology in Turkish hamsters housed in one of four conditions: long days (LD) at 22°C, short days (SD) at 22°C, SD at 5°C, and SD at 13°C. Body temperature and torpor use were monitored with implanted radio transmitters, and teeth were examined postmortem. Teeth of SD hamsters had narrower, less distinct circadian increments than teeth of LD hamsters, and hibernation at both 5°C and 13°C was associated with very narrow, sharply defined increments. At 5°C the number and cumulative width of hibernation increments were related to number and cumulative duration of periodic arousals, although this relationship was not detected at 13°C. This investigation adds to a growing body of work on the effects of hibernation on hard tissue morphology, and has implications for the study of hibernation behavior in evolutionary and historical contexts.