Magnetic sensitivity

"Magnetic alignment in grazing and resting cattle and deer"
http://www.pnas.org/content/early/2008/08/22/0803650105.abstract

European researchers showed that cattle and deer tend to align themselves with Earth's magnetic field.
The researchers surveyed worldwide Google Earth images of 8,510 cattle in 308 pastures and plains. They also recorded the body positions of 2,974 wild deer in 277 locations in the Czech Republic and found that both animals appear to face either north or south direction along with magnetic north but not geographic north. It is known that birds, turtles, and fish use magnetic guidance in migration. The authors say that this is the first study about magnetic field detection in large mammals. Furthermore, it seems that no one has ever used Google Earth for biological studies.
In Japan, cattle usually face north-south direction in cowshed to avoid direct sunshine. Perhaps it has a beneficial effect on milk production.


At a good time, I found an interesting report about the magnetic sensitivity.

"Cryptochrome mediates light-dependent magnetosensitivity in Drosophila"
http://www.nature.com/nature/journal/v454/n7207/abs/nature07183.html

The authors showed that the ultraviolet-A/blue-light photoreceptor cryptochrome (Cry) is necessary for magnetosensitive responses in fruit flies.
Cry proteins play a role in the generation and maintenance of circadian rhythms in mammals, but the Cry-dependent magnetosensitivity in Drosophila was light sensitive and did not require the function of circadian clock. The authors say that this is the first genetic evidence for a chemical-based magnetosensitive system in any animal. The relation between Cry-based magnetic sensing and animal orientation and navigation is an interesting subject in future studies.