Editing Magnetoreception (section)

==== Electromagnetic induction ====

[[File:Yellow Stingray, Belize, 2007-09.jpg|thumb|upright=1.2|The [[yellow stingray]] is able to sense the intensity and [[magnetic dip|inclination angle of a magnetic field]].<ref name="Newton Gill Kajiura 2020" />]]

Another possible mechanism of magnetoreception in animals is electromagnetic induction in [[cartilaginous fish]], namely [[shark]]s, [[stingray]]s, and [[chimaera]]s.  These fish have [[Electroreception|electroreceptive]] organs, the [[ampullae of Lorenzini]], which can detect small variations in [[electric potential]]. The organs are mucus-filled and consist of canals that connect pores in the skin of the mouth and nose to small sacs within the animal's flesh. They are used to sense the weak electric fields of prey and predators. These organs have been predicted to sense magnetic fields, by means of [[Faraday's law of induction]]: as a conductor moves through a magnetic field an electric potential is generated. In this case the conductor is the animal moving through a magnetic field, and the potential induced (V<sub>ind</sub>) depends on the time (t)-varying rate of magnetic flux (Φ) through the conductor according to
<math display="block">V_{ind}=-\frac{d\phi}{dt}</math>

The ampullae of Lorenzini detect very small fluctuations in the potential difference between the pore and the base of the electroreceptor sac. An increase in potential results in a decrease in the rate of nerve activity. This is analogous to the behavior of a current-carrying conductor.<ref>{{cite journal |last1=Blonder |first1=Barbara I. |last2=Alevizon |first2=William S. |date=1988 |title=Prey Discrimination and Electroreception in the Stingray ''Dasyatis sabina'' |journal=[[Copeia]] |volume=1988 |issue=1 |pages=33–36 |doi=10.2307/1445919 |jstor=1445919}}</ref><ref>{{cite journal |last=Kalmijn |first=A. J. |date=1 October 1971 |title=The Electric Sense of Sharks and Rays |url=http://jeb.biologists.org/content/55/2/371 |journal=[[Journal of Experimental Biology]] |volume=55 |issue=2 |pages=371–383 |doi=10.1242/jeb.55.2.371 |pmid=5114029 |doi-access=free |bibcode=1971JExpB..55..371K }}</ref><ref name="Anderson Clegg Véras Holland 2017" /> [[Sandbar shark]]s, ''Carcharinus plumbeus'', have been shown to be able to detect magnetic fields; the experiments provided non-definitive evidence that the animals had a magnetoreceptor, rather than relying on induction and electroreceptors.<ref name="Anderson Clegg Véras Holland 2017 ">{{cite journal |last1=Anderson |first1=James M. |last2=Clegg |first2=Tamrynn M. |last3=Véras |first3=Luisa V. M. V. Q. |last4=Holland |first4=Kim N. |title=Insight into shark magnetic field perception from empirical observations |journal=[[Scientific Reports]] |volume=7 |issue=1 |date=8 September 2017 |page=11042 |doi=10.1038/s41598-017-11459-8 |pmid=28887553 |pmc=5591188 |bibcode=2017NatSR...711042A }}</ref> Electromagnetic induction has not been studied in non-aquatic animals.<ref name="Rodgers Hore 2009" />

The [[yellow stingray]], ''Urobatis jamaicensis'', is able to distinguish between the intensity and inclination angle of a magnetic field in the laboratory. This suggests that cartilaginous fishes may use the Earth's magnetic field for navigation.<ref name="Newton Gill Kajiura 2020">{{cite journal |last1=Newton |first1=Kyle C. |last2=Gill |first2=Andrew B. |last3=Kajiura |first3=Stephen M. |date=2020 |title=Electroreception in marine fishes: chondrichthyans |journal=[[Journal of Fish Biology]] |volume=95 |issue=1 |pages=135–154 |doi=10.1111/jfb.14068 |pmid=31169300 |s2cid=174812242 |doi-access=free }}</ref>