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This is how migratory birds orient themselves

However, it is convenient to remember that these are two different senses, and that animals that have both can take advantage of one or the other as they see fit. For example, it has been observed that during the migration of the hoary shearwater (Calonectris leucomelas), the youngest and most inexperienced specimens rely more on their magnetic sense, even if this means crossing dangerous mountainous areas; while the more experienced adults take advantage of their ability to detect changes in direction to avoid mountain ranges and take advantage of more efficient and less risky detours. Although this supposes them to deviate from the original course, they are able after correcting their direction to return to their original course.

Other animals have even more complex systems. Some birds, and also sea turtles, are capable not only of orienting themselves in a north-south direction, but also of establish mental maps that stay aligned with the magnetic field. This allows them to establish, in familiar terrain, new routes that improve the efficiency of the trip, and in this way, invest less energy in migration.

And in addition, other animals, including many ruminants, rodents or bats, are also capable of orienting themselves on a north-south axis, and, to this day, we do not know exactly how they do it. Although some hypotheses point to the existence of pigments called cryptochromes, which would align according to the magnetic field under certain conditions, much remains to be investigated. There are still many experimental studies to be done on orientation mechanisms in animals.

References:

Burda, H. et al. 1990. Magnetic compass orientation in the subterranean rodent Cryptomys hottentotus (Bathyergidae). Experience, 46(5), 528-530. DOI: 10.1007/BF01954256

Kishkinev, D. et al. 2021. Navigation by extrapolation of geomagnetic cues in a migratory songbird. Current Biology, 31(7), 1563-1569.e4. DOI: 10.1016/j.cub.2021.01.051

Pakhomov, A. et al. 2018. Magnetic map navigation in a migratory songbird requires trigeminal input. Scientific Reports, 8(1), 11975. DOI: 10.1038/s41598-018-30477-8

Takahashi, S. et al. 2022. Head direction cells in a migratory bird prefer north. Science Advances, 8(5), eabl6848. DOI: 10.1126/sciadv.abl6848

Wu, L.-Q. et al. 2012. Neural Correlates of a Magnetic Sense. Science, 336(6084), 1054-1057. DOI: 10.1126/science.1216567

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