Age affects hibernation in Syrian hamsters (Mesocricetus auratus).

In this study, we aimed to show how age affects hibernation in the Syrian hamster. Experimentally, we used 30 male animals differing in age. The old animals were 20 months of age and the adults were 8 months of age at the end of the test. The young animals were 3 weeks old at the start of testing and 5 months old at the end of the testing period. The torpor observation started October 15, 1996, and ended March 11, 1997, in the laboratory colony maintained under natural photoperiod and outdoor air. Observations were performed around noon daily. Three measures (i.e., prehibernation period [hibernation latency], proportion of hibernation spent in torpor, and proportion of animals in torpor), all of which reflect the strength of occurrence of hibernation, indicated that the older hamsters (1) started hibernation earlier, (2) spent more time in torpor, and (3) had a higher chance of being in torpor than the younger ones during the hibernation season.