How Do Turtles Breathe While They Hibernate?

Turtles, belonging to the reptile family, have cold-blooded metabolic systems that require outside heat to provide the energy for movement and to sustain life. With the approach of winter, aquatic turtles can not survive the harsh temperatures and must go into hibernation. Since they cannot migrate like birds to escape adverse weather, they submerge themselves in ponds or lakes, to wait out the freezing temperatures, until the climate warms. Turtles have found a way to breathe underwater and survive during hibernation.

  1. Hibernation Time Cycle

    • Nearly all true aquatic turtles hibernate, either fully or sporadically during the winter. This can last as long as four months. They seek shelter around the start of autumn. Some species of turtles, like the stinkpot, snapper and soft-shelled species begin hibernation in October. The timing also depends on whether or not the onset of winter comes early, with an abrupt change in temperature.

    Metabolic Rate

    • Turtles possess a normal warm climate metabolism that functions roughly 10 times slower than warm-blooded mammals of the same size. During the winter months, a turtle's metabolism will drop another 10 to 20 percent. A turtle's summer heart rate is about 40 beats per minute. A turtle's heart rate will drop to one beat every 10 minutes during winter hibernation.

    Survivable Temperature

    • Aquatic turtles seek the bottom of lakes, streams and ponds, where a typical ice sheet forms over the surface, cutting off escape from the water. An aquatic turtle can survive a temperature range no lower than 2 degrees below freezing during winter. A typical micro-climate safe zone exists in lakes, streams and ponds which reaches and stays at approximately 39 degrees Fahrenheit. Turtles seek out this oxygen sufficient 39-degree zone and stay there until spring brings warmer temperatures.

    Oxygen Aborption

    • Turtles have lungs but are unable to use them underwater. The have no gills to trap oxygen. Turtles have specially designed throats and mouths which have special linings that trap minute oxygen air molecules, and absorb them into very small capillaries. However, this does not fully oxygenate the turtle's system. An additional pair of thin-walled sacs in proximity to the anus traps and dissolves minute amounts of oxygen. The throat and mouth, in conjunction with the anal sacs, creates a barely detectable pumping action which intakes oxygen from both sides of the body and distributes it.

    Toxic Disposal

    • When the turtle absorbs oxygen through the throat and anal sacs, large stores of carbon dioxide and lactic acid build up in its body. They cannot breathe to expel it. Instead their shells emit calcium salts, which enter the bloodstream and neutralize the toxic gases and chemicals. The process is similar to the way calcium carbonate dilutes and neutralizes stomach acid in a human.