The need for salt excretion in reptiles (such as [[marine iguana]]s and [[sea turtle]]s) and birds (such as [[petrel]]s and [[albatross]]es) reflects their having much less efficient [[kidney]]s than mammals, as marine mammal kidneys can deal with sea-water.<ref>{{cite web|url=http://www.ansci.cornell.edu/plants/adapt/salt.html |title=Plants Poisonous to Livestock - Cornell University Department of Animal Science |publisher=Ansci.cornell.edu |accessdate=2011-07-14}}</ref> Unlike the [[skin]] of [[amphibian]]s, that of reptiles and birds is impermeable to salt, preventing its release.<ref name="Hazard">{{cite book | last = Hazard | first = Lisa C. | title = Sodium and Potassium Secretion by Iguana Salt Glands | work = Iguanas: Biology and Conservation | publisher = University of California Press | pages = 84–85 | year = 2004 | isbn = 978-0-520-23854-1 }}</ref>▼
▲TheA neednecesidade forde saltexcreción excretionde insales reptilesen réptiles (suchcomo as [[marine iguana mariña|iguanas mariñas]]sande [[seatartarugas turtlemariñas]]s) ande birdsaves (suchcomo as [[petrelpardela]]s ande [[albatrossalbatros]]es) reflectsreflicte theirque havingteñen much less efficientuns [[kidneyril]]ses thanmoito mammalsmenos eficientes que os dos mamíferos, asxa marineque mammalos kidneysriles candos deal[[mamíferos withmariños]] sea-waterpoden tratar a auga do mar.<ref>{{cite web|url=http://www.ansci.cornell.edu/plants/adapt/salt.html |title=Plants Poisonous to Livestock - Cornell University Department of Animal Science |publisher=Ansci.cornell.edu |accessdate=2011-07-14}}</ref> UnlikeA thediferenza da [[skinpel]] ofdos [[amphibiananfibios]]s, thata ofdos reptilesréptiles ande birdsaves isé impermeable toao saltsal, preventingimpedindo a itssúa releaseliberación.<ref name="Hazard">{{cite book | last = Hazard | first = Lisa C. | title = Sodium and Potassium Secretion by Iguana Salt Glands | work = Iguanas: Biology and Conservation | publisher = University of California Press | pages = 84–85 | year = 2004 | isbn = 978-0-520-23854-1 }}</ref>
The evolution of a salt gland in early reptiles and birds allowed them to eat aquatic plants and animals with high salt concentrations. This evolutionary development does not account for the gland in [[elasmobranchs]], suggesting [[convergent evolution]].
A evolución das glándulas de sal nos primeiros réptiles e aves permitiulles comer plantas acuáticas e animais con altas concentracións de sal. Este desenvolvemento evolutivo non explica as glándulas dos [[elasmobranquios]], seguramente orixinadas por [[converxencia evolutiva]].
Algunhas teorías suxiren que os condutos lacrimais dos mamíferos e as [[glándula sudorípara|glándulas sudoríparas]] pode ser relacionados evoltivamente coas glándulas do sal.
Some theories suggest [[mammal]]ian [[tear duct]]s and [[sweat gland]]s may be evolutionarily related to salt glands. While human tears are high in [[potassium]], most [[phylogeny|phylogeneticists]] disagree with the association.{{Citation needed|date=September 2011}}
