Many animals navigate using the Earth’s magnetic field as though they have their own personal compasses. Birds, for example, can use the Earth’s magnetic poles to navigate during migration. Even monarch butterflies are able to use magnetic field lines although it’s more of a secondary navigation method for them. While scientists have already observed the symptoms of an internal compass in some animals, they have never pinpointed the exact part providing these navigation abilities until now. Magnetosensation describes an organism’s ability to inherently detect the magnetic field lines of Earth. This ability has been observed in numerous organisms from sharks to worms. Researchers and engineers at the University of Texas at Austin (UT) were finally able to detect the microscopic sensor that gives one species of worm to burrow through the dirt without getting lost. They found a microscopic antenna-like structure inside a tiny roundworm called Caenorhabditis elegans (C. elegans).

How Does the Magnetic Sensor Work?

A nanoscale sensor located at the end of a neuron inside the roundworm’s brain gives it the ability to sense the planet’s magnetic field. Scientists were able to find the sensor after altering the magnetic field around the worms. As a result of the alterations or magnetic pole shift, the worms became disoriented and unable to determine which way was up and which was down. Usually the worms would dig downward in order to find food but when the poles were reversed they moved in random directions. The scientists decided to test their theory on worms from different corners of the world such as Europe, Australia, Hawaii, etc. They found that the worms all dug in the direction the magnetic field would have indicated as downward in their original homes. The discovery suggests that other species living in the dirt could have similar sensors in their brains to help them navigate. The worm’s sensor may also help scientists locate the source of magnetosensitivity in animals living above ground. You can observe the magnetosensation of animals if you have a dog. When dogs circle before they lie down or mark their territory, they are aligning with the magnetic force of Earth. Have you noticed your dog do this?   Image by Bob Goldstein