Sea turtles primarily remove excess salt from their bodies through specialized glands located near their eyes.
Understanding Salt Excretion in Sea Turtles
Living in a saltwater environment means sea turtles constantly ingest salt, both from the water they drink and the food they eat. Managing this high salt intake is crucial for their survival, as excessive salt can disrupt their internal balance. Unlike mammals, reptilian kidneys are unable to excrete large volumes of salt via urine. This limitation means they require an alternative, more efficient method for salt removal.
The Specialized Salt Glands
To overcome the limitations of their kidneys, sea turtles have evolved a unique solution:
- Specialized Secretory Glands: Sea turtles evolved specialised secretory glands (lachrymal glands) located in the corner of each eye to remove excess salt. These glands are highly efficient at concentrating salt from the bloodstream and expelling it.
- Location: These glands are situated near the eyes, in the corner closest to the nose.
- Process: The glands actively filter salt from the blood, producing a highly concentrated saline solution.
- Appearance: The liquid secreted from these glands gives the appearance of tears, hence why turtles are often reported to “cry”. This visible "crying" is simply the process of excess salt being expelled from the body, not an emotional response.
Essentially, these lachrymal glands function like extra-renal (outside the kidney) salt-excreting organs, allowing sea turtles to maintain proper hydration and electrolyte balance while inhabiting marine environments.
