Comparative Physiology

Comparative physiology examines the diversity of mechanisms by which animals—from invertebrates to mammals—maintain homeostasis, exploit ecological niches and respond to environmental challenges. By contrasting organ-system function, molecular pathways and whole-organism responses across species, this discipline reveals how natural selection has sculpted solutions to recurring problems such as thermoregulation, oxygen supply, metabolic control, water balance and locomotion. Key themes include evolutionary innovations in energy conservation (for example torpor and hibernation in mammals, freeze tolerance in ectotherms), adaptive remodelling of cardiovascular and respiratory systems to support varied modes of activity (flight, diving, burrowing), and the regulation of cellular stress responses to extremes of temperature, hypoxia and osmotic pressure. Comparative studies integrate field observations, laboratory experiments and modelling to uncover conserved principles—such as the interplay of membrane transporters, enzymatic kinetics and signal-transduction networks—while highlighting how species-specific traits arise from modifications of shared ancestral programmes. These insights underpin applications ranging from wildlife conservation under climate change to the design of biomimetic devices and novel medical therapies that harness natural stress-resistance mechanisms.

Research from Nature Portfolio

Neuronal circuits that govern energy-saving torpor have been manipulated noninvasively in rodents using targeted transcranial ultrasound. Activation of hypothalamic preoptic area neurons stabilises a torpor-like state for over 24 hours through TRPM2 channel signalling and suppression of brown adipose thermogenesis, paving the way for external control of metabolic depression. Global phylogenetic analyses of desert bird communities predict species-specific physiological impacts of future warming by integrating biophysical models with distribution data. These studies identify climatic refugia and reveal that vulnerability to heat stress is unevenly distributed among taxa, underscoring the need for targeted conservation of low-impact regions. Investigations into thermal melanism in dragonflies show that seasonal shifts in colouration optimise heat absorption in low-insolation periods, with darker assemblages emerging in early and late flight seasons. This phenological adaptation suggests a mechanistic link between pigmentation, behavioural timing and thermal ecology across broad geographic scales.

Research from all publishers

In goldfish skeletal muscle, short-term moderate hypoxia upregulates Nrf2, superoxide dismutase and HSP70 without altering mitochondrial content, while prolonged exposure induces PGC-1α expression. This two-phase antioxidant and mitochondrial-dynamic response maintains contractile performance under low-oxygen conditions. In desert lizards, climate warming initially reduces gut microbial diversity but long-term warming increases both diversity and short-chain fatty acid–producing taxa, with faecal transplants from warmed donors enhancing host antibacterial activity and immune gene expression. These findings link temperature-driven microbiota shifts to ectotherm health and thermal tolerance. Comparative transcriptomics of high-altitude Rana kukunoris reveal winter-specific upregulation of antifreeze proteins, glucose transporters and urea synthesis enzymes, alongside ribosome and energy-supply pathways. Tissue-specific gene networks support cryoprotectant accumulation and metabolic reshaping, illuminating genetic strategies for surviving subzero environments.

Comparative Physiology publication trend

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

Technical terms

Torpor: A reversible state of metabolic suppression and reduced body temperature that conserves energy during adverse conditions.

Thermal melanism: Increased dark pigmentation in ectotherms to enhance solar heat absorption and thermoregulation in cooler environments.

Biophysical model: A mechanistic representation that predicts organismal physiological responses by combining physical laws with biological parameters.

Nrf2: A transcription factor that regulates antioxidant gene expression in response to oxidative stress.

PGC-1α: A co-activator that controls mitochondrial biogenesis and energy metabolism under varied environmental stimuli.

Short-chain fatty acids (SCFAs): Microbially produced metabolites that modulate host immune function, energy homeostasis and gut barrier integrity.

References

1. Induction of a torpor-like hypothermic and hypometabolic state in rodents by ultrasound. Nature Metabolism (2023).
2. Global patterns of climate change impacts on desert bird communities. Nature Communications (2023).
3. Seasonal variation in dragonfly assemblage colouration suggests a link between thermal melanism and phenology. Nature Communications (2023).
4. Effects of environmental hypoxia on the goldfish skeletal muscle: Focus on oxidative status and mitochondrial dynamics. Journal of Contaminant Hydrology (2024).
5. Gut microbiota modulation enhances the immune capacity of lizards under climate warming. Microbiome (2024).
6. Comparative transcriptomic analysis delineates adaptation strategies of Rana kukunoris toward cold stress on the Qinghai-Tibet Plateau. BMC Genomics (2024).