Editing Turtle (section)

=== Thermoregulation ===
[[File:Two basking cooter turtles (5861462496).jpg|thumb|Smaller pond turtles, like these [[northern red-bellied cooter]]s, regulate their temperature by basking in the sun.|alt=cooter turtles basking in sunshine near their pond]]

Turtles, like other reptiles, have a limited ability to [[Homoiotherm|regulate their body temperature]]. This ability varies between species, and with body size. Small pond turtles regulate their temperature by crawling out of the water and basking in the sun, while small terrestrial turtles move between sunny and shady places to adjust their temperature. Large species, both terrestrial and marine, have sufficient mass to give them substantial [[thermal inertia]], meaning that they heat up or cool down over many hours. The [[Aldabra giant tortoise]] weighs up to some {{convert|60|kg|lb}} and is able to allow its temperature to rise to some {{convert|33|C|F}} on a hot day, and to fall naturally to around {{convert|29|C|F}} by night. Some giant tortoises seek out shade to avoid overheating on sunny days. On [[Grand Terre Island]]<!--part of Aldabra-->, food is scarce inland, shade is scarce near the coast, and the <!--Aldabra giant--> tortoises compete for space under the few trees on hot days. Large males may push smaller females out of the shade, and some then overheat and die.<ref name="Pough Janis 2019"/>

Adult sea turtles, too, have large enough bodies that they can to some extent control their temperature. The largest turtle, the leatherback, can swim in the waters off [[Nova Scotia]], which may be as cold as {{convert|8|C|F}}, while their body temperature has been measured at up to {{convert|12|C-change|F-change}} warmer than the surrounding water. To help keep their temperature up, they have a system of [[countercurrent heat exchange]] in the blood vessels between their body core and the skin of their flippers. The vessels supplying the head are insulated by fat around the neck.<ref name="Pough Janis 2019">{{cite book |last1=Pough |first1=F. Harvey |last2=Janis |first2=Christine M. |chapter=16. Turtles |title=Vertebrate Life |publisher=Sinauer Associates |publication-place=New York |year=2019 |edition=10th |isbn=978-1-60535-607-5 |oclc=1022979490 |pages=283–299}}</ref>