Bottlenose dolphins have an electric super sense that could help them navigate the oceans and hunt fish.

The aquatic mammals are born with two rows of whiskers along their snouts, which drop off soon after birth.

The dimples left are now discovered to be a sophisticated sensory mechanism allowing them to detect weak electric fields.

Tim Hüttner and Guido Dehnhardt, from University of Rostock, Germany, tested the sensitivity of two dolphins, Donna and Dolly, to these fields.

The dolphins were trained to rest their jaws on a metal bar and were taught to swim away within five seconds upon sensing an electric field, gradually decreasing in strength.

The team kept track of how many times the dolphins departed within five seconds and found Donna and Dolly were equally sensitive to the strongest fields.

The next experiment saw fluctuating electric fields applied to replicate those produced by living animals, such as the pulsing movements of fish gills.

When pulsing the electric fields at 1, 5 and 25 times per second, while reducing the field strength, the dolphins could still sense the fields.

However, their sensitivity was less than compared to unvarying electric fields.

Dolly was only able to detect the slowest field at 28.9 μV cm−1, while Donna picked up all three oscillating fields, sensing the slowest at 11.7 μV cm−1.

In the real world, the researchers believe this sensory ability is useful to sense fish hidden in sediment at close range.

The study, published in the Journal of Experimental Biology, explains "thresholds determined for bottlenose dolphins in the present study would indicate that they can detect the same fish species considered for sharks at a distance of 3–7 cm."

Furthermore, the researchers speculate that dolphins' electric sensitivity might contribute to a larger-scale navigation system.

Guido Dehnhardt explains that as dolphins navigate through weaker areas of the Earth's magnetic field at standard speeds, they could generate detectable electric fields of 2.5 μV cm−1 across their bodies. This sensory adaptation potentially allows them to harness the Earth's magnetic field for navigation.

As the dolphins increase their swimming speed, their likelihood of perceiving the planet's magnetic field grows, providing a potential avenue for dolphins to navigate across vast distances using their electric sense as a magnetic map.

The study authors believe their findings opens up a new field of research with the potential to find answers to unexplained phenomena, such as the correlation between live whale strandings and geomagnetic anomalies.