Animal Physiology - Biophysics

Animal physiology encompasses the physical and chemical processes that sustain life, spanning scales from molecular machines to whole organisms. Biophysics applies quantitative frameworks—mechanics, fluid dynamics, thermodynamics and electromagnetism—to unravel how animals generate force, transmit signals and maintain homeostasis. At the cellular interface, electrophysiology decodes ionic currents underlying neural and cardiac excitability, while mechanotransduction transforms mechanical cues into biochemical responses via cytoskeletal dynamics and membrane proteins. Molecular motors such as myosin and kinesin convert chemical energy into directed movement, orchestrating intracellular transport and muscle contraction. In tissues and organs, fluid–structure interactions guide blood perfusion, respiratory exchange and aquatic propulsion, with scaling laws linking form and function across body sizes. Thermoregulatory strategies integrate heat production and loss to cope with environmental challenges. Emerging multi-scale approaches—high-resolution imaging, micro-extensometry, patch-clamp assays and computational modelling—foster integrative insights into complex physiological phenomena, from cellular nano-mechanics to collective behaviours and bioinspired technologies.

Research from Nature Portfolio

Recent work has established universal scaling relations in undulatory swimmers, revealing that tail-beat frequency scales with body length through a crossover near 0.5–1 m; below this threshold, muscle physiology dictates oscillation rates, whereas above it fluid–structure interaction imposes an inverse length dependence to prevent cavitation at high speeds. Investigations into collective propulsion have shown that followers in swimming pairs can save energy by adopting a linear phase shift—vortex phase matching—relative to leading counterparts, a strategy demonstrated in both live fish and biomimetic robots and effective without visual or lateral-line feedback. Foundational hydrodynamic analyses of animal swimming have reinterpreted thrust generation, showing that many species primarily draw themselves forward by creating low-pressure regions—suction-based propulsion—rather than by pushing on the surrounding fluid, with implications for the design of efficient bioinspired vehicles.

Research from all publishers

Other recent studies have refined measurements of thrust at micronewton scales, with direct force-transducer experiments quantifying the rowing force of water-strider middle legs and revealing that image-based estimates may underestimate propulsive effort. At the millimetre scale, magnetically actuated flexible sheets on water surfaces have demonstrated capillary and added-mass-driven undulatory propulsion, where tuning of actuation frequency, bending stiffness and amplitude controls waveform and energy efficiency. Structural biology of the microvascular endothelium has been advanced by elucidation of an alpha-helical coiled-coil arrangement in plasmalemma vesicle-associated protein (PLVAP), offering a molecular basis for diaphragms that define fenestral sieving and regulate capillary permeability.

Animal Physiology - Biophysics publication trend

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

Technical terms

Electrophysiology: The study of ion-driven electrical currents in cells that underlie membrane excitability and signal propagation in nerves and muscles.

Mechanotransduction: Conversion of mechanical forces into biochemical signals within cells, typically via cytoskeletal networks and membrane proteins.

Fluid–structure interaction: The coupled dynamics between moving bodies or tissues and the surrounding fluid, governing propulsion and perfusion.

Vortex phase matching: A strategy in collective swimming or flight in which neighbouring individuals adopt a phase shift aligning with shed vortices to reduce energy expenditure.

Suction-based propulsion: Thrust generation via the creation of dominant low-pressure regions around a body, effectively pulling the animal forward rather than pushing on the fluid.

Fenestrae: Pore-like openings in specialised capillary endothelia, often spanned by diaphragm proteins, that enable selective passage of small molecules and proteins.

References

1. Scaling the tail beat frequency and swimming speed in underwater undulatory swimming. Nature Communications (2023).
2. Vortex phase matching as a strategy for schooling in robots and in fish. Nature Communications (2020).
3. Suction-based propulsion as a basis for efficient animal swimming. Nature Communications (2015).
4. Analysis of Rowing Force of the Water Strider Middle Leg by Direct Measurement Using a Bio-Appropriating Probe and by Indirect Measurement Using Image Analysis. Cyborg and Bionic Systems (2023).
5. Undulatory Propulsion at Milliscale on Water Surface. Advanced Science (2024).
6. Structural insights into plasmalemma vesicle-associated protein (PLVAP): Implications for vascular endothelial diaphragms and fenestrae. Proceedings of the National Academy of Sciences of the United States of America (2023).