Can Turtles Breathe Out Of Their Butt?
Many species of turtles such as sliders, Japanese pond turtles, painted turtles, and many others, can stay submerged underwater for extended periods (several months).
This is necessary when they need to hibernate during winter when the temperatures drop below freezing and most ponds are covered in a lid of ice.
How do these turtles breathe under ice-covered ponds where the turtle cannot resurface to breathe?
Well, turtles can breathe through their butt. To be precise they can respire through their butt through a process known as cloacal respiration. Of course, turtles also commonly breathe air through nostrils located above the mouth.
How Long Can Turtles Go Without Breathing Air?
We have established that some turtles can respire through their butts. But this is technically not breathing but rather respiration. Additionally, this form of respiration is only effective when the turtle is hibernating.
During hibernation, the turtle doesn’t move, and their heart rate drops significantly. Metabolism is so low that only a handful of bodily functions are carried out.
Cloacal respiration cannot provide enough oxygen for an active turtle. So how many minutes can an active turtle go without breathing air?
Depending on their level of activity, a turtle that isn’t hibernating can remain underwater for several hours (4 to 7 hours while they sleep). An active turtle generally needs to only come up to breath every 10 to 30 minutes.
However a stressed and frightened turtle, for instance, one trapped in a fishing net, can use up all its stored oxygen within a few minutes and drown.
A Turtle’s Respiratory System
Many turtles respire by breathing air using their nostrils (external nares) and also by passing water over/through their cloaca (butt) and throat.
Turtles are unique because of their shell. As you may or may not know, the turtle’s shell is part of its body.
The turtles’ rib is part of its shell. As such, turtles are one of the few animals which are required to breathe oxygen in an inflexible casing, the shell. The shell cannot expand and contract the way most animals, including humans, do.
Instead, the turtle uses a muscle sling attached to the shell to pump air in and out of the lungs. The muscle sling is a prerequisite for the development of the turtle’s rigid shell.
Turtles breathe air through nostrils (external nares). From there the air passes through the glottis and into the trachea. From there the air enters the two bronchi and then the lungs.
The spongy lung is made up of a network of faveoli (theses are air passages). Oxygen can then enter the bloodstream from here.
Turtles may be air-breathing reptiles but they can respire enough oxygen to survive through months of hibernation underwater.
Because turtles are cold-blooded, as the temperature of their environment changes so does their internal temperature. As such a 1 °C change in water temperature leads to a 1 °C change in body temperature.
Such animals (including other reptiles and amphibians) are known as ectotherms. Humans and other mammals maintain a constant body temperature regardless of external temperatures.
As endotherms when external temperatures are low, we burn food to generate body heat.
A drop or rise in our internal body temperature is usually a sign that something is wrong (for instance, high body temperature is usually a sign of illness).
On the other hand, a drop or rise in a turtle’s body temperature simply means that there is a drop or rise in the temperature of the turtle’s environment.
As such, turtles regulate their body temperature by alternating between basking and swimming.
When temperatures are low so is the turtle’s metabolism, and when temperatures are high, so is the turtle’s metabolism. When metabolism is high, the turtle turns more energy and can be more active.
During winter, temperatures everywhere are low. As such the turtle’s metabolism slows down.
The turtle is less active, burns less energy and needs less oxygen to survive. During this time, their oxygen needs can be met by oxygen diffused in the water.
Turtles absorb the needed oxygen by moving water over body surfaces that are flush with blood vessels. These body surfaces include the throat, and the butt (technically called the cloaca).
The cloaca is a rear opening where bodily waste is excreted from. Turtles respire through cloaca by expanding and contracting specialized muscles there.
This forces water in and out of the cloaca. The high concentration of blood vessels located there allows turtles (such as painted turtle and Japanese pond turtle) to absorb oxygen from the water.
Other turtles such as musk turtles use a similar technique to absorb oxygen into blood vessels located in the throat rather than in the cloaca.
For turtles to respire oxygen successfully underwater, the oxygen content in the water has to be high. However, this is usually not the case over the entire hibernation period.
As the winter drags on, the amount of oxygen in the pond reduces to hypoxic (low oxygen) levels. The pond may even become depleted of oxygen.
At this stage, turtles such as painted turtles and snapping turtles can survive using anaerobic respiration & metabolism as well as active chemical buffering processes.
This leads to a buildup of lactic acids. To combat this buildup, some turtles such as the painted turtle mobilizes calcium to neutralize the acid.
Regardless, this acid buildup is similar to what happens after vigorous exercise where the human body switches from aerobic to anaerobic respiration.
Can Turtles Drown?
We know that turtles can respire underwater and even go months without breathing, but can turtles drown? Yes, they can. Regardless of all the adaptations that allow turtles to stay underwater longer than almost all other reptiles, they can still drown under certain conditions.
The amount of oxygen burnt by a turtle depends on the metabolic rate of the turtle, and since metabolism is tied to temperature, it needs to be very cold for the turtle to be able to rely solely on cloacal respiration.
Similarly, even if the turtle isn’t hibernating, the turtle needs to be inactive to remain underwater for hours.
If the turtle is actively swimming, then it needs to resurface to breathe air every 10 to 30 minutes depending on the species.
A turtle that is trapped and struggling to escape can drown within minutes as they burn through their oxygen deposits very quickly trying to escape. Aquariums built to accommodate turtles mustn’t have any objects that can trap the pet turtles.
Cloacal respiration which is the main way turtles respire when hibernating underwater is the main way through which the get the needed oxygen to stay alive.
This type of breathing is done through the butt. This process is more of diffusing oxygen into the blood and releasing carbon dioxide out.
The oxygen supplied to the turtle with this type of respiration is minimal and surviving on this requires slow metabolism which is achieved because of the drop in temperature during winter.
And if the oxygen diffused in the pond runs low, the turtle can always rely on anaerobic respiration.
However, due to the buildup of lactic acid, this type of respiration is not sustainable. However, it is enough to ensure that the turtle can survive through the harsh winter.