Many turtle enthusiasts worry whether turtles might forget to breathe and drown while hibernating underwater. However, there is something you may not know: turtles can also breathe through their cloaca.
Turtles are reptiles, lacking gills and breathing with lungs just like us. Therefore, when living in water, they need to regularly surface to breathe. This can be quite troublesome, especially during hibernation when their activity significantly decreases, making it difficult to surface for air. Over time, they have evolved the ability for “cloacal respiration”.
They have two large cloacal bladders, also known as cloacal bursae, located in their pelvic region. The surface of these bladders is densely covered with cilia and rich in capillaries, which are used for gas exchange to provide oxygen to the turtles. However, this method is less efficient, accounting for only four percent of the total oxygen consumption. Fortunately, turtles are poikilothermic animals, and their heart rate is very low during hibernation, with only two beats per minute at its lowest, thus requiring very little oxygen.
In addition to this, turtles also perform auxiliary “breathing” through their skin during hibernation. The oxygen exchanged through the cloaca and skin is entirely sufficient, so there is no need to worry about turtles being suffocated while sleeping in the winter.
Original article by KPTer, if reproduced, please cite the source: https://www.kaipet.com/en/turtles-drown-hibernating-underwater-learn-cloacal-respiration
