Thermogenic Regulation in Small Mammals

Small mammals deploy an integrated suite of mechanisms to sustain core temperature in variable environments. At the physiological level, they balance basal metabolic heat production with adaptive processes such as shivering and non-shivering thermogenesis in brown adipose tissue. Key molecular regulators include uncoupling protein 1, thyroid hormones and sympathetic neurotransmitters, which orchestrate mitochondrial activity and fuel mobilisation. Plasticity of the thermoneutral zone allows animals to adjust metabolic rate across seasons or altitudes, while behavioural strategies—huddling, nesting and postural changes—further reduce heat loss. Recent work has emphasised the role of gut microbiota in modulating host energy expenditure, revealing bidirectional communication between microbial metabolites and thermogenic pathways. Genetic adaptations in high-altitude species demonstrate enhanced expression of peroxisome proliferator-activated receptors and co-activators that drive “browning” of white fat. Together, these interlocking responses underpin survival in cold climates, inform our understanding of energy balance in endotherms and suggest new avenues for managing thermogenic function in ecological and biomedical contexts.

Research from Nature Portfolio

Studies of a tropical tree shrew have shown that exposure to winter-like temperatures elevates body mass, protein content and cytochrome c oxidase activity in liver and brown fat, indicating that photoperiod and temperature jointly upregulate thermogenic capacity. Metabolomic profiling of a montane vole species across distinct sites revealed that variation in serum and hepatic metabolites correlates with ambient temperature and altitude, suggesting metabolic reprogramming supports differential heat production. Intracerebroventricular administration of leptin in chronically cold-acclimated rats demonstrated that central leptin chiefly enhances physical activity rather than non-shivering thermogenesis, highlighting a behavioural axis to hormonal regulation of energy expenditure.

Thermogenic Regulation in Small Mammals publication trend

The graph below shows the total number of articles in thermogenic regulation in small mammals across all publications each year (not limited to Nature Index journals).

Technical terms

Non-shivering thermogenesis (NST): metabolic generation of heat in specialised tissues without muscle contractions.

Brown adipose tissue (BAT): fat depot rich in mitochondria that produces heat via uncoupling protein 1.

Uncoupling protein 1 (UCP1): inner-mitochondrial membrane protein facilitating proton leak to generate thermal energy.

Thermoneutral zone (TNZ): ambient temperature range where basal metabolic rate suffices for thermal homeostasis.

Browning: transformation of white adipocytes to a brown-like phenotype with elevated thermogenic capacity.

Gut microbiota: community of intestinal microorganisms that influence host metabolic and immune functions.

Huddling: social clustering behaviour that reduces individual heat loss and metabolic demand.

References

1. Gut Microbial Community and Host Thermoregulation in Small Mammals. Frontiers in Physiology (2022).
2. Huddling Conserves Energy, Decreases Core Body Temperature, but Increases Activity in Brandt's Voles (Lasiopodomys brandtii). Frontiers in Physiology (2018).
3. Differential Expression of Metabolism-Related Genes in Plateau Pika (Ochotona curzoniae) at Different Altitudes on the Qinghai–Tibet Plateau. Frontiers in Genetics (2022).
4. Role of thermal physiology and bioenergetics on adaptation in tree shrew (Tupaia belangeri): the experiment test. Scientific Reports (2017).
5. Metabolomics of Eothenomys miletus from five Hengduan Mountains locations in summer. Scientific Reports (2019).
6. Intracerebroventricular administration of leptin increase physical activity but has no effect on thermogenesis in cold-acclimated rats. Scientific Reports (2015).