The question of whether squirrels urinate from their eyes often arises due to certain observed behaviors, but the short answer is no. As mammals, squirrels share a common biological blueprint for waste elimination, relying on a specialized internal system, not the eyes. This widespread rumor stems from the misinterpretation of natural squirrel behavior.
The Biological Verdict
Squirrels, like all mammals, possess a standard lachrymal apparatus designed exclusively for ocular health. The lachrymal glands produce tears, a watery, protein-rich fluid used to lubricate the eye’s surface, clean away foreign particles, and protect against bacteria.
These tears flow across the eye and drain through small openings called puncta, leading into the nasolacrimal duct, which empties into the nasal cavity. This system is structurally separate from the urinary tract and does not connect to the bladder or kidneys. Furthermore, the chemical composition of tears is fundamentally different from urine, lacking high concentrations of metabolic waste products like urea.
The Source of the Misconception
The belief that squirrels excrete liquid from their eyes stems from their frequent and visible scent-marking behaviors. Squirrels use chemical communication extensively to convey information about territory, social status, and reproductive condition. They have specialized scent glands located on various parts of their bodies, including near the mouth and cheeks, which they rub on objects in their environment.
While there is no definitive evidence of a “preorbital” scent gland near the eyes, the action of rubbing their face and cheek glands often looks like they are wiping a liquid from the ocular area. This oily or musky secretion contains pheromones and is deposited on tree trunks and branches to mark a travel route or boundary. Observers confuse this glandular secretion with the act of urination.
How Squirrels Actually Urinate
The process of waste elimination in squirrels follows the universal mammalian pattern. The kidneys filter the blood, extracting metabolic waste products, excess salts, and water to create urine. This urine, which contains the nitrogenous waste product urea, travels from the kidneys down the ureters to the urinary bladder.
The urine is stored in the bladder until the squirrel releases it through the urethra. Squirrels frequently urinate on the ground or on tree trunks as they move along their routes, which also serves as a form of territorial marking, especially during the breeding season. This act of waste excretion is confined to the genitourinary system, far removed from the eyes.