Editing Sea turtle (section)

==== Navigation ====

Below the surface, the sensory cues available for navigation change dramatically.<ref name=":16">{{Cite journal|last1=Lohmann|first1=K. J.|last2=Lohmann|first2=C. M. F.|last3=Endres|first3=C. S.|date=2008-06-01|title=The sensory ecology of ocean navigation|journal=Journal of Experimental Biology |volume=211|issue=11 |pages=1719–1728|doi=10.1242/jeb.015792 |pmid=18490387|issn=0022-0949|doi-access=free|bibcode=2008JExpB.211.1719L }}</ref> Light availability decreases quickly with depth, and is refracted by the movement of water when present, celestial cues are often obscured, and ocean currents cause continuous drift.<ref name=":16" /> Most sea turtle species [[Sea turtle migration|migrate]] over significant distances to nesting or foraging grounds, some even crossing entire ocean basins.<ref name=":17">{{cite journal|last1=Lohmann|first1=Kenneth J. |last2=Putman|first2=Nathan F. |last3=Lohmann|first3=Catherine M. F.|date=2012|title=The magnetic map of hatchling loggerhead sea turtles|url=https://linkinghub.elsevier.com/retrieve/pii/S0959438811001954|journal=Current Opinion in Neurobiology |volume=22|issue=2|pages=336–342 |doi=10.1016/j.conb.2011.11.005 |pmid=22137566|s2cid=1128978|url-access=subscription}}</ref> Passive drifting within major current systems, such as those in the [[North Atlantic Gyre]], can result in ejection well outside of the temperature tolerance range of a given species, causing heat stress, hypothermia, or death.<ref name=":17" /> In order to reliably navigate within strong [[Ocean gyre|gyre]] currents in the open ocean, migrating sea turtles possess both a bicoordinate magnetic map and magnetic compass sense, using a form of navigation termed [[Magnetoreception]].<ref name=":17" /><ref name=":16" /><ref name=":18">{{cite journal |last1=Lohmann |first1=Kenneth J. |last2=Lohman |first2=Catherine M. F. |date=2019-02-06|title=There and back again: natal homing by magnetic navigation in sea turtles and salmon |journal=The Journal of Experimental Biology |volume=222|issue=Supplement 1 |pages=jeb184077 |doi=10.1242/jeb.184077 |pmid=30728225 |issn=0022-0949|doi-access=free|bibcode=2019JExpB.222B4077L }}</ref> Specific migratory routes have been shown to vary between individuals, making the possession of both a magnetic map and compass sense advantageous for sea turtles.<ref name=":17"/>

[[File:Hatchling green sea turtle.jpg|alt=Hatchling green sea turtle in the sand photographed by USFWS Southeast|thumb|Hatchling green sea turtle in the sand photographed by USFWS Southeast]]

A bicoordinate magnetic map gives sea turtles the ability to determine their position relative to a goal with both latitudinal and longitudinal information, and requires the detection and interpretation of more than one magnetic parameter going in opposite directions to generate, such as [[Magnetic field intensity]] and [[Inclination angle]].<ref name=":18" /><ref name=":20">{{Cite journal|last1=Fuxjager|first1=M. J.|last2=Eastwood|first2=B. S.|last3=Lohmann|first3=K. J.|date=2011-08-01|title=Orientation of hatchling loggerhead sea turtles to regional magnetic fields along a transoceanic migratory pathway |journal=Journal of Experimental Biology |volume=214|issue=15|pages=2504–2508 |doi=10.1242/jeb.055921|pmid=21753042 |issn=0022-0949 |doi-access=free|bibcode=2011JExpB.214.2504F }}</ref> A magnetic compass sense allows sea turtles to determine and maintain a specific magnetic heading or orientation.<ref name=":20" /> These magnetic senses are thought to be inherited, as hatchling sea turtles swim in directions that would keep them on course when exposed to the magnetic field signatures of various locations along their species' migratory routes.<ref name=":20" /><ref>{{Cite journal |last=Lohmann|first=K. J. |date=2001-10-12 |title=Regional Magnetic Fields as Navigational Markers for Sea Turtles |url=https://www.science.org/doi/10.1126/science.1064557 |journal=Science |volume=294 |issue=5541 |pages=364–366 |doi=10.1126/science.1064557 |pmid=11598298 |bibcode=2001Sci...294..364L |s2cid=44529493|url-access=subscription }}</ref>

[[Natal homing]] behavior is well described in sea turtles, and genetic testing of turtle populations at different nesting sites has shown that magnetic field is a more reliable indicator of genetic similarity than physical distance between sites.<ref name=":21">{{Cite journal|last1=Brothers|first1=J. Roger |last2=Lohmann|first2=Kenneth J.|date=2018|title=Evidence that Magnetic Navigation and Geomagnetic Imprinting Shape Spatial Genetic Variation in Sea Turtles |journal=Current Biology |volume=28|issue=8 |pages=1325–1329.e2 |doi=10.1016/j.cub.2018.03.022 |pmid=29657117|doi-access=free|bibcode=2018CBio...28E1325B }}</ref> Additionally, nesting sites have been recorded to "drift" along with isoline shifts in the magnetic field.<ref name=":22">{{Cite journal|last1=Brothers|first1=J. Roger|last2=Lohmann |first2=Kenneth J.|date=2015|title=Evidence for Geomagnetic Imprinting and Magnetic Navigation in the Natal Homing of Sea Turtles|journal=Current Biology |volume=25|issue=3 |pages=392–396 |doi=10.1016/j.cub.2014.12.035 |pmid=25601546|doi-access=free|bibcode=2015CBio...25..392B }}</ref> Magnetoreception is thought to be the primary navigation tool used by nesting sea turtles in returning to natal beaches.<ref name=":21" /><ref name=":22" /> There are three major theories explaining natal site learning: inherited magnetic information, socially facilitated migration, and geomagnetic [[Limbic imprint|imprinting]].<ref name=":18" /> Some support has been found for geomagnetic imprinting, including successful experiments transplanting populations of sea turtles by relocating them prior to hatching, but the exact mechanism is still not known.<ref name=":18" />