A Novel Phenomenon Predicting the Entry into a State of Hibernation in Syrian Hamsters (Mesocricetus auratus)

Abstract

ABSTRACT. When Syrian hamsters (Mesocricetus auratus) are bred in a cold and short-day environment, most animals go into hibernation after a certain period of time. However, to date it has not been possible to predict which hamster will enter hibernation. In this study, we subcutaneously implanted thermo-loggers in hamsters bred in the cold environment, and recorded the subcutaneous temperature at short intervals until they went into hibernation. A time series analysis of temperature disclosed that a fall of 0.4 to 0.8°C in subcutaneous temperature was seen 5 to 16 days before entering hibernation, and this phenomenon continued for three days or more. No hamster went into the hibernation without displaying this signal. Although the mechanism by which this phenomenon takes place is not clear, it is a sign from the body, which is useful for indicating if a hamster will enter hibernation shortly. KEY WORDS: hamster, hibernation, temperature.J. Vet. Med. Sci. 67(2): 215-217, 2005 Recently, much attention has been paid to hibernating animals because of their use in investigating the preservation of tissues and organs at low temperature, and organ injuries of ischemia-reperfusion [1]. Hibernating mammals such as ground squirrels (Spermophilus lateralis), chipmunks (Tamias asiaticus) and hedgehogs (Erinaceus europaeus) have been frequently studied. However, for research, it is important to use animals that easily hibernate in all the seasons of the year under control of environmental conditions rather than seasonal hibernators. The Syrian hamster (Mesocricetus auratus) is an animal that satisfies this qualification [8,9]. When hamsters are transferred from a euthermic and long-day photoperiod breeding room to a temperature-controlled cold environment, they start hibernation after a certain period of time. However, from our findings as shown in Table 1, all hamsters that are transferred to cold environments do not always enter hibernation. Furthermore, it is still difficult to predict which hamster will go into hibernation. Development of a telemetry system has enabled us to know at which stage of the hibernation process the hamster belongs by measurering changes in the body temperature [7]. However, this telemetry system is subject to interference caused by various electrical equipment in the laboratory environment [6], making it difficult to conduct a detailed analysis, such as an analysis of 24-hr moving average of the body temperature. In this study, we investigated the hibernation process of Syrian hamsters to obtain fundamental data on hibernation and to examine whether or not the data contains indicator signs of hibernation. For this purpose, hamsters were acclimated to a cold environment, and body temperature was analyzed for the period until they went into hibernation by implanting a button-type thermologger.Syrian hamsters were bred in our animal facilities and the experiments using the hamsters were performed in accordance with a guideline issued by our institutional animal experiment review board. Female ...

Thermoregulatory changes anticipate hibernation onset by 45 days: data from free-living arctic ground squirrels

“…In a population of free-living marmots, Arnold et al (2011) found that T b began to decline 14 days prior to hibernation. Arai et al (2005) found that captive Syrian hamsters significantly decreased T b 5-16 days prior to hibernation, and animals that did not decrease T b did not enter hibernation. Similarly, Christian and Geiser (2007) found that free-living sugar gliders that entered torpor lowered resting T b in the preceding 3 days, while those that did not enter torpor did not lower T b .…”

“…This is suggested to be due to a progressive resetting within hypothalamic regions that control T b set-point and thermoregulation (Strumwasser 1958(Strumwasser , 1960Hammel 1967;Heller and Colliver 1974;Luecke and South 1972;Pivorun 1976;Lyman et al 1982). Recently, it has been shown that 13-lined ground squirrels expressed irregular use of daily torpor prior to multiday torpor (Russell et al 2010), and that Syrian hamsters exhibit a small decrease in subcutaneous temperature 5-16 days before their first torpor (Arai et al 2005). However, these studies were conducted under laboratory conditions, and thermoregulatory patterns prior to hibernation in free-living animals are not well understood.…”

Seasonal variations in physical activity and implications for human health

“…Others have noted a modulation of leptin eVectiveness in the weeks preceding hibernation; this allows an accumulation of body fat reserves for the winter months (Kronfeld-Schor et al 2000). Hamsters show a 0.4-0.8°C fall of subcutaneous temperature 5-16 days before they begin hibernating, but it is not clear whether this body cooling is a primary event, or is a consequence of other events leading up to hibernation (Arai et al 2005).…”

The role of endogenous H2S formation in reversible remodeling of lung tissue during hibernation in the Syrian hamster

“…It is interrupted by bouts of arousal during which metabolism and other parameters normalize (Carey et al, 2003). Notably, the hibernating animal withstands significant organ damage (Arai et al, 2005) and mechanisms applied by hibernators to alleviate organ damage may have potential application to human biology and medicine, addressing issues such as resistance to ischemia and hypothermic organ preservation, prevention of muscle atrophy and even the development of inducible torpor as an aid in acute medicine or surgery (Morin and Storey, 2009;Zancanaro et al, 1999).…”