A recent study addresses the ability of sea turtles to detect north-south direction, also known as spontaneous magnetic alignment. It is based on an exotic sensory system based on a quantum process and special photoreceptor functions.
Professor John Phillips compared the phenomenon to the visual effects we experience when we close our eyes after looking at light. The fatigued receptors in our case create patterns that are not actually present in nature. However, turtles and a number of other creatures see something similar thanks to the sensing of magnetic fields.
This peculiar visual effect is a special coordinate system that allows animals to orient themselves in space. Instead of determining the direction from point A to point B, they use magnetic fields to determine their location in an unknown environment.