Animal Internal Navigation Systems

The Earth's magnetic field runs in curves all around the globe from the south magnetic pole to the north magnetic pole. Animals equipped with internal compasses are able to navigate by analyzing its direction, intensity or inclination to determine their location or direction.

Dogs are famous for their incredible sense of smell, which scientists estimate is between 10,000 and 100,000 times more powerful than that of humans. But scientists have recently discovered that dogs also determine directional and positional information from the Earth's magnetic field.

We Caribbean spiny lobsters deploy our internal magnetic field detector while walking in the vicinity of our dens and during our seasonal migrations. And, as nocturnal marine animals, we can also easily use this to find our way back to our shelters after foraging in the sea. It is our innate geographic localization system that allows us, the spiny lobsters, to navigate the vast and dark seas by interpreting changes in the Earth’s magnetic field.

In the summer, loggerhead sea turtles lay their eggs on the eastern coast of Florida, USA. Guided by the Earth’s magnetic field and other environmental clues, their hatchlings know which direction to walk in order to return quickly to the sea. These valiant little ones then accomplish one of the longest and most spectacular migrations in the animal kingdom. The hatchlings use their internal compasses applying their inherited inner magnetic analyzers to courageously surmount the North Atlantic Gyre and navigate 12,875 kilometers through four ocean currents in the region of the Sargasso Sea to finally reach the safety of the open sea.

Our flying friends are just as incredible with navigation. Homing pigeons can journey 1,800 kilometers and determine the exact location of their homes. Scientists believe that homing pigeons navigate using both the Earth’s magnetic field and the position of the sun. Consequently, when the weather is overcast, pigeons can become disoriented. Migratory birds such as zebra finches and European robins have a special protein called cryptochrome in their eyes which might help them to see magnetic fields just like we see colors.

It is not just avian species that are equipped with such navigation systems. An example from the realm of mammals is the African mole rats, who spend most of their time building complex underground tunnel networks. Despite very poor vision, they scamper around their tunnels quite easily because they can detect the Earth's magnetic field through their eyesight, in a similar way to how the European robins probably can!