One of these two things is true.
Either, Nature is a cruel and fickle mistress, that has made two creatures look very similar and have significantly different biology.
Or, Humanity is just really, stunningly unobservant of fairly obvious biological differences, and likes to imagine things it thinks look similar are somehow the same.
We’re not about to decide which of those statements is true for you, but they have an impact on the question of how long a tortoise can hold its breath, and how long they can stay underwater for.
Consider the Tortoise
- Large, heavy, dome-like shell.
- Feet, as used by land animals for getting from place to place.
- Generally, fairly slow in their movements.
- Has a fairly ordinary butt
- Sinks like the stone it largely resembles if dropped into water.
- Drowns quickly, very much unlike a stone, if dropped into water.
Now Consider the Aquatic Turtle
- Relatively flat, lighter shell.
- Flippers, as used by aquatic animals for getting from place to place.
- Generally, fairly fast in their movements.
- Has a frankly awe-inspiring butt.
- Swims like a… well, like a turtle if dropped into water.
- Can stay submerged in hibernation mode for months on end.
That humans still get tortoises and turtles confused is ridiculous and shocking – not least to the tortoises, who many times have been ‘rescued’ by people throwing them into water, in the mistaken belief that they are turtles. In fact, it’s been so ridiculous and shocking, they’ve frequently died as a result.
But there’s a relevant point there.
If you return a turtle to the water, it will swim away from you, popping up occasionally to fill its lungs with oxygen, and go about its turtle-business, none the worse for the encounter.
If you ‘return’ a tortoise to the water, it will try as hard as it can to get right the heck back out again and escape from the demented, species-blind human that’s actively trying to torture it to death.
And if it doesn’t succeed, then in a very little while, the tortoise will sink beneath the water. And there, very often in a matter of minutes, it will die.
Because the truth is, while they’re generally slightly better at holding their breath than we are, the usual amount of time a tortoise can hold its breath, and thus survive underwater, is between 1-3 minutes.
You’ve seen how fast a tortoise moves on land, right?
You’ve been in the sea yourself, yes? Felt how difficult it is to walk against the weight of the water?
That’s one seriously dead tortoise you have there.
A tortoise is not just a turtle that’s slumming it on land, any more than we are chimpanzees on a break from all that climbing and swimming and living in trees.
So why is it lots of people still expect tortoises to be able to hold their breath for hours and survive underwater all that time?
Well…that’s where everything we’ve said so far gets a little… tricky.
That’s because, while they’re different in lots of ways, turtles and tortoises do have a couple of things in common. Firstly, they’re both reptiles. And secondly, they both hibernate.
Now, as any of the mammals who’ve taken to the hibernation habit could show you by their actions, for mammals, hibernation is an energy-intensive thing.
We either need to stock up on fat-rich foods before we do it (like bears), or collect a lot of hibernation snacks to see us through the big sleep (like squirrels).
And in addition to the collection of energy to see them through, mammalian hibernators slow their metabolisms right down, so they become much more energy efficient and less demanding on their environment.
This is where people make their big observational mistake about hibernation. It’s not just a big sleep. It’s more akin to a big meditation class that lasts all winter.
Heart rates are greatly reduced, energy expenditure is reduced, and to put it very… humanly… the creatures bliss out as much as they sleep.
Turtles and tortoises are reptiles, they don’t have to do any of the energy gathering business, but their hibernation is otherwise incredibly similar to the mammalian version.
The heart rate slows dramatically, but over time, so as not to push the system into shock. The energy demands made by the body reduce to just a ripple above zero, and the same sort of state is reached. Very little movement, very little demand, incredible survival through a kind of sleep that’s more like meditation.
The Hibernation Exception
We know what you’re thinking. What has any of this got to do with how long tortoises can hold their breaths for? We’ve already told you that in the normal run of things, tortoises have a couple of minutes underwater before they, like we, are out of the game of life.
One of the main reasons this question about tortoises and breath-holding comes up is because there is a lot of anecdotal evidence for tortoises having, for instance, fallen into garden ponds.
And then, seemingly miraculously, for them being discovered hours later, and revived when they’ve been removed, like chronically depressed rocks, and allowed to come to their senses.
How, given the handful of heartbeats before they normally drown, is this phenomenon possible?
The answer seems to be that if the water into which they fall is cold enough, tortoises can enter a state of emergency hibernation. They can almost immediately reduce the demand their bodies have for oxygen, and so can sometimes survive hours underwater – uncorroborated reports suggest they can do this for up to 24 hours.
Ultimately, unless rescued, they’re still going to die, because having a heavy, domed shell and feet works against them in terms of rising to the surface to get the oxygen they need, and they have an ordinary butt.
Oh, the turtle’s awe-inspiring butt? When it’s hibernating and its need for oxygen is sparse, the turtle can effectively absorb oxygen through its butt (or cloaca) – allowing it to stay submerged all winter.
The tortoise, with its relatively ordinary butt and heavier shell… can’t breathe that way. And so, unless rescued, it will eventually drown.
So, while under normal circumstances, most types of tortoise will drown after just a few minutes underwater, they may survive in colder water for anything from a couple of hours to a day. Whether this counts as them ‘holding their breath’ is arguable, but in the right circumstances, they can make their last breath of air last astonishingly long.