Turtles often appear to shed tears, which many mistake for human-like sadness. However, this watery discharge is not a sign of distress or pain. While the sight of a “crying” turtle can evoke empathy, this phenomenon has a purely biological explanation. These tears serve a vital function, allowing turtles to thrive in their diverse habitats.
Salt Glands
The tears observed in turtles are produced by specialized organs known as salt glands. In marine turtles, these glands are primarily located behind the eyes, often referred to as modified lacrimal glands, similar to human tear glands. These salt glands are remarkably efficient, sometimes even larger than the turtle’s brain, enabling significant salt excretion. They function as miniature desalination plants, actively extracting excess salt from the bloodstream.
These glands consist of numerous secretory tubules lined with specialized cells. These cells actively transport sodium chloride from the blood into the tubules. The concentrated saline solution then flows through ducts that empty near the eyes, resulting in the visible “tears.” While most prominent in marine species, salt glands are also present in some freshwater and terrestrial turtles, as well as other marine reptiles and seabirds.
The Need for Salt Excretion
Turtles, especially those in marine environments, face a constant physiological challenge: maintaining their internal balance of water and salt, a process known as osmoregulation. Marine turtles consume significant amounts of saltwater through their diet and by living in their aquatic environment. Unlike mammals, whose kidneys efficiently filter and excrete excess salt, reptilian kidneys are less capable of handling high salt concentrations.
This physiological limitation means that without a specialized mechanism, salt accumulation would lead to dehydration and could become toxic. The salt glands serve as a critical adaptation, removing excess sodium chloride to prevent internal osmotic imbalance. This enables marine turtles to maintain proper hydration and electrolyte levels, allowing them to survive in an environment significantly saltier than their internal body fluids.
Common Scenarios for “Crying”
The “tears” from a turtle’s salt glands become most noticeable in specific situations. Marine turtles, for instance, are frequently observed “crying” when they come ashore to nest. During this nesting process, the salt glands are active, and since there is no water to dilute the secretions, the tears are clearly visible. These secretions also help to lubricate the eyes and flush away sand that might enter during nest excavation.
Similarly, any time a turtle is out of the water for an extended period, such as when basking or undergoing examination, these salty secretions may become apparent. The tears are a continuous physiological process, whether the turtle is in the water or on land, but they are diluted and thus unseen in their aquatic habitat. Therefore, the appearance of a turtle “crying” is a normal, healthy function, not an indication of emotional distress or discomfort.