Turtles are air-breathing reptiles that can drown, despite their deep connection to aquatic environments. They rely on lungs, similar to land animals, to obtain oxygen. If a turtle is submerged for too long without access to the surface, it can indeed suffocate.
Turtle Respiration and Underwater Adaptations
Turtles breathe using lungs, located beneath their carapace. Unlike fish, they do not possess gills to extract oxygen directly from water. To live in water while needing air, turtles have developed physiological adaptations allowing them to remain submerged for extended periods.
One adaptation is their ability to hold their breath for considerable durations. While actively swimming or foraging, many turtles surface every few minutes, but they can typically hold their breath for 20 to 60 minutes. When resting, sleeping, or in cold water, their breath-holding capacity increases significantly, sometimes allowing them to stay underwater for several hours, with some records indicating up to seven hours.
Their ectothermic, or cold-blooded, nature allows extended submersion. In colder water, their metabolic rates slow, lowering oxygen demand and conserving oxygen in blood and muscles. Some freshwater turtles also use cloacal respiration, absorbing small amounts of oxygen from water through cloacal tissues, especially when inactive or brumating. This method is inefficient compared to lung respiration, primarily supplementing oxygen during low activity.
Circumstances Leading to Drowning
Turtles can drown when their ability to reach the surface for air is compromised. Entanglement in submerged objects like fishing nets, plastic debris, or discarded lines can trap turtles, preventing them from ascending. A stressed turtle, struggling to free itself, will rapidly deplete its stored oxygen, potentially leading to drowning.
Injury or illness also makes turtles vulnerable to drowning. A weakened turtle may lack the strength to swim to the surface for air. This is particularly true for pet turtles in tanks if they become overturned or get trapped under decorations or rocks, preventing them from reaching an air pocket.
Cold-stunning is a significant cause of drowning for wild sea turtles. When water temperatures drop below 50°F (10°C), turtles experience hypothermia, becoming lethargic and unable to swim effectively. Cold-stunned turtles often float helplessly, and prolonged exposure can lead to respiratory failure and drowning. Mass cold-stunning events have resulted in thousands of turtles needing rescue.
Preventing Drowning Incidents
Preventing drowning incidents for pet turtles involves careful attention to their habitat. For aquatic turtles, the water depth in their tank should be appropriate for their size, allowing them to swim freely and easily reach the surface. Providing easy access to a dry basking area, such as a ramp or platform, is important, ensuring they can completely exit the water to warm up and dry off. Owners should regularly check the tank for any potential traps, like loose rocks or decorations, where a turtle could get stuck.
For wild turtles, preventing drowning centers on human responsibility and environmental stewardship. Disposing of fishing gear, plastic bags, and other debris properly is crucial to minimize entanglement risks. Avoiding the disturbance of turtles in their natural habitats also helps prevent stress and injury. If a wild turtle is found entangled, injured, or appearing cold-stunned, contact local wildlife authorities or rescue organizations for assistance.