- Their Shell Is an Integrated Part of Their Body (It Cannot Be Removed): Unlike in cartoons, a turtle can never leave its shell. The shell is formed by the evolutionary fusion of the turtle's spine, ribs, and breastbone. It contains nerve endings and blood vessels, meaning turtles can actually feel when their shell is touched, petted, or tapped. - Some Species Can Breathe Through Their Butt (Cloaca): Certain freshwater turtles (such as the Fitzroy River turtle), especially while hibernating or staying beneath ice-covered lakes for extended periods, absorb oxygen through specialized, blood-vessel-rich structures in their rear opening called the cloaca. Known as cloacal respiration, this process allows them to extract oxygen directly from the water without surfacing. - Their "Tears" Are a Way to Excrete Excess Salt: When sea turtles appear to be "crying" while laying eggs on land, it is not a sign of distress. Because they constantly swallow saltwater, specialized salt glands located behind their eyes pump out excess salt from their bodies. This process keeps their internal salt levels balanced while also flushing sand out of their eyes. - Their Sex Is Determined by Nest Temperature: In most turtle species, sex isn't determined by chromosomes, but rather by the temperature of the sand or soil during incubation (Temperature-Dependent Sex Determination). If eggs develop in warmer temperatures, they hatch as females, whereas cooler temperatures produce males.