Sea turtles drink seawater to hydrate. Although sea turtles are physically adapted to a saline environment, they need to be able to excrete excess salt. As reptilian kidneys are unable to excrete large volumes of salt via urine, sea turtles evolved specialised secretory glands (lachrymal glands) located in the corner of each eye to remove excess salt. The liquid secreted gives the appearance of tears, hence why turtles are often reported to “cry” .
- Reina, R.D. Jones, T.T. and Spotila, J.R. 2002. Salt and water regulation by the leatherback sea turtle Dermochelys coriacea. Journal of Experimental Biology, 205(13), 1853-1860.