On moonless nights between February and April along Odisha’s coast, the sand begins to stir. Olive ridley hatchlings, no larger than a child’s palm, tear free from their shells and push through the sand to brave the foamy surf seaward. They have never tested these waters. No parent waits to lead them. Yet, in minutes in shallow water, their bodies orient with startling precision, maintaining a steady offshore course into the Bay of Bengal, as if responding to a signal beyond sight.
This instinctive alignment to an unseen force recurs across the animal kingdom. Shorebirds descend from the steppes of Central Asia onto India’s wetlands. Warblers arrive from Siberia, navigating continents. Butterflies ride monsoon winds across peninsular distances. Each migration is steered by brains no larger than a pea.
Scientists call the phenomenon magnetoreception: the ability to sense Earth's magnetic field. It is often described as biology’s most elusive sense. And the implications of its research are believed to reach far beyond animals.
Geographically, India sits astride the Central Asian Flyway, one of Earth’s busiest avian highways, funneling millions of globetrotters overhead each season. Yet studies on magnetic navigation in the subcontinent are limited. In a 2021 experiment, biologists Tushar Tyagi and Sanjay Kumar Bhardwaj of Ch. Charan Singh University in Meerut gently rotated the horizontal component of Earth’s magnetic field for night-migrating red-headed buntings. The Indian-wintering birds responded, shifting their flight directions, offering evidence that these tiny migrants navigate with a functional magnetic compass.
At labs in Japan, Europe and the United States, researchers are peering into the brains of migratory animals, trying to decipher how the planet’s faint magnetic field is translated into neural code. Researchers, including Sanjay Kumar Bhardwaj, note that the focus is on identifying the precise molecule where these quantum-level reactions occur, maintaining that it has the potential to push the limits of biology itself.
In birds, one leading hypothesis centres on light-sensitive cryptochrome proteins in the retina, where quantum radical-pair reactions involving unpaired electrons may allow magnetic fields to subtly shape visual processing.
Another strand of research points to microscopic iron-based particles called magnetite, thought to function as biological sensors that may relay signals to the brain via the trigeminal nerve (the cranial nerve carrying sensory information from the face and beak). These remain competing clues; the molecular and cellular machinery of magnetoreception, according to sensory biologists, is still enigmatic.
Even as neuroscientists wrestle with the curious case of magnetoreception in animals, existing theories hint at a deeper possibility: humans may not be entirely without it. As biologist Tushar Tyagi observed, the more we learn about how animals read the planet, the harder it is to believe we are entirely cut off from it.
"So many species are believed to sense Earth’s magnetic field as naturally as we see or hear. Why would we be an exception? But this is not settled science. It remains unproven, and the findings do not imply humans possess a conscious magnetic sense," says Professor Kousik Sarathy Sridharan, Head (Heritage Science & Technology) and Associate Professor of Biomedical Engineering at IIT Hyderabad.
A few studies abroad (2019 Caltech experiment) suggest that this capacity may lie buried beneath awareness; not merely waiting in the dark to be discovered, but actively working within it, without our knowing. In that work, controlled rotations of Earth-strength magnetic fields triggered drops in alpha brain waves (8–13 Hz), a neural signature of sensory detection and attention shift, though the findings are debated.
Professor Sridharan notes that researchers have long known oxygenated and deoxygenated blood behave differently in magnetic fields. Hemoglobin carrying oxygen is diamagnetic, while deoxygenated hemoglobin is paramagnetic, interacting weakly with magnetic fields. This contrast underpins functional MRI, which maps brain activity by detecting subtle magnetic changes associated with shifts in blood oxygenation.
He cautions, however, that such comparisons must be made carefully. "MRI scanners typically operate at 1.5–3 tesla, whereas Earth’s magnetic field is only about 50 microtesla (tens of thousands of times weaker)." Whether biological systems can naturally detect signals that weak is an open scientific question.
Magnetoreception may not feature among the themes of the ongoing BioAsia 2026 in Hyderabad, but the summit’s emphasis on TechBio, the convergence of biology, AI-driven analytics, molecular engineering, and high-precision instrumentation, reflects the very toolkit global researchers rely on to probe subtle sensory mechanisms. A reminder that breakthroughs in one corner of biology often hinge on tools forged in another.
