Earth's magnetic field can be described as a magnetic dipole, which can be used as a useful compass for navigation. Magnetoreception is the the ability of many species to detect the magnetic field in order to determine the direction, height and position in space and by using these senses, they are capable of navigating in space. It is most studied in birds, whose detection of Earth's magnetic field is very important for navigation during migrations. In addition to birds, this ability have many other species including bacteria, fungi, insects (especially bees) and the higher animals such as turtles, crabs, sharks and rays.Although numerous studies have been conducted, it is still not fully clarified how magnetoreceptors function.Several factors makes locating magnetoreceptors extremely difficult. One of them is the fact that the magnetic field passes freely through biological tissue. During the last three decades there has been suggested a number of different mechanisms that could provide the basis for detecting magnetic fields. But the latest researches are focused on three possibilities: electromagnetic induction, chemical reactions depending on the magnetic field, and biogenic magnetite.Among these three mechanisms, perhaps most important is that referring to the chemical magnetoreception. If magnetoreception occurs in photoreceptors, then there is the interesting possibility that the process involves cryptochrome, photosensitive group of proteins that are involved in the circadian system of plants and animals.