Territory aggression and energy budget in food-restricted striped hamsters

Behavior and physiology in female Cricetulus barabensis are associated with the expression of circadian genes

The circadian clock regulates the behavior, physiology, and metabolism of mammals, and these characteristics, such as sleep-wake cycles, exercise capacity, and hormone levels, exhibit circadian rhythms. Light signaling is the main stimulator of the mammalian circadian system. The photoperiod regulates the reproductive cycle of seasonal breeding animals, and the circadian clock plays a pivotal role in this process. However, the role of the clock in coordinating animal behavior and physiology in response to photoperiodic changes needs further investigation. The present study investigated the changes and correlation of behavioral activities, physiological indicators, and gene expression in female striped hamsters (Cricetulus barabensis) within 24 h under a 12L:12D photoperiod. We found that the daily rhythms of sleep-wake and open field were significant in hamsters. The expression of clock genes, melatonin receptor genes, and genes involved in general metabolism oscillated significantly in central and peripheral tissues (brain, hypothalamus, liver, ovary, and thymus) and was significantly associated with behavior and physiology. Our results revealed that the neuroendocrine system regulated the rhythmicity of behavior and physiology, and central and peripheral clock genes (Bmal1, Clock, Per1, Per2, Cry1, and Cry2), melatonin receptor genes (MT1, MT2, and GPR50), and metabolizing genes (SIRT1, FGF21, and PPARα) played important roles. Our results suggest that central and peripheral circadian clocks, melatonin receptors, and genes involved in general metabolism may play key roles in maintaining circadian behavior and metabolic homeostasis in striped hamsters. Our results may have important implication for rodent pest control.

Preliminary investigation into the housing of dwarf hamsters

BACKGROUND

Although pet hamsters are widely available, the literature on their husbandry and health is limited, and guidelines for the care of hamsters are variable. This study investigated housing in different dwarf hamster species, focusing on factors affecting co-housing failure.

METHODS

An online cross-sectional survey shared on social media investigated potential factors influencing co-housing failure of dwarf hamsters in captivity, such as sex, species and resources provided.

RESULTS

The majority of hamsters had not received veterinary care and were provided with fewer food and water sources than animal numbers, while 12% were kept in enclosures less than 75 cm in length. Co-housing failure was more likely in dwarf hamsters older than 6 months (odds ratio 4.75, p = 0.005, 95% confidence interval = 1.607-14.13). There was no association found between sex or species and co-housing failure.

LIMITATIONS

There was likely a degree of selection bias as the owners who completed the questionnaire may have had more knowledge of dwarf hamster husbandry than the general population of owners.

CONCLUSION

Key welfare concerns regarding dwarf hamster care in captivity were identified as inadequate enclosure sizes, a high prevalence of co-housing failure arising from aggression, especially in hamsters more than 6 months old, and inadequate resource provision for many pair- or group-housed animals. Further investigation of the welfare impacts of resource provision deficits is required.