Snapping Turtles Are Impossible - Update
In honour of 50 Canadianimals videos, this is a brand new update of one of our most popular episodes, with new footage and narration. In it, we discover the wild, borderline impossible numbers around snapping turtle births and deaths to see exactly how ‘timeless’ these prehistoric relics are, and how fragile that makes them today.
EPISODE NOTES
A big source for this episode was the amazing book Algonquin Wildlife: Lessons in Survival by Norm Quinn, which details some of the insane stories around biologists stationed in Algonquin Park and the lengths they would go for esoteric studies. It’s a great read (I read it twice on one canoe trip) with some indelible images - some you might wish weren’t so indelible. The description of clusters of ticks on a moose hanging ‘like bunches of grapes’ will never leave my mind. You’re welcome.
Part of the impetus for this update was the fact that, in the years since posting the original, I’ve caught more snapping turtles on film, including some newborns on the Humber River in Toronto. The turtle you see digging a nest (she didn’t actually deposit any eggs when I was there) was on a well-trodden public path in Ottawa along the Rideau River.
TRANSCRIPT
In celebration of 50 videos, this is an update of one of our ‘greatest hits’ episodes, with new footage and narration.
Snapping turtles look like they still belong in a prehistoric swamp. And that’s kinda true - they’ve been around for 90 million years. But it wasn’t until recently that we found out just how timeless they really are.
In late summer of 2022 I was canoeing the Rideau Canal. At our last stop we stepped out of the canoe to find this.
The size and spherical shape of the eggshells tells us that this was a snapping turtle nesting site.
Snapping turtles emerge to lay eggs in May or June. They look for sandy or gravely areas, and use their powerful legs to dig a bowl-shaped nest, into which they’ll deposit around 25 to 45 eggs. Rarely, they might lay a second batch in the fall.
But evidence suggests that this particular nest we’d found ended up as somebody’s lunch.
The way the nest has been dug out completely points to a predator - and snapping turtle nests have no shortage of those. Rats, raccoons, foxes, skunks, opossums, otters, minks, crows… some of them can sniff out the eggs even when they’re buried.
And if the idea of a snapping turtle nest being ransacked and devoured strikes you as a little tragic… well, buckle up.
Exploring the area, I found some other nests, also devoured. And that is no surprise. Because the hard numbers around snapping turtle reproduction… are just ridiculous.
A lot of this info was taken from a study in Algonquin Park that started in the early 1970s.
Their focus was population biology - what are the birth and death rates of snapping turtles. And the conclusion of the study, not in their words, was basically: ‘no snapping turtle is ever born or ever dies’.
OK, that can’t literally be true, but let’s use some numbers so we can see how close to true that actually is.
Say we start with a hypothetical 100 snapping turtle eggs. Right away, 80 will be found and eaten by predators.
Of the 20 that are left, 5 will hatch into baby turtles. And something as simple as a cooler summer can prevent those from hatching at all.
Now, of those 5 baby turtles, how many will grow up to be 18-year-old adults? Statistically? Zero.
Just their first emergence from the nest and crossing to a nearby body of water is often fatal. They’re contending with hungry predators, but also, remember I said snapping turtles look for sandy or gravely spots to dig their nests. That means they’re tragically drawn to the sides of roads and paths. Newborn turtles might have to contend with foot traffic, bikes, or cars. In other words, the moments after hatching are already a deadly obstacle course.
OK, back to our numbers: so 100 eggs statistically gets us zero adult turtles. What if we started with 200 eggs? How many of those get to adulthood? Zero. Start with 500 eggs? Zero. A thousand? Zero.
So how many eggs does a snapping turtle need to lay to get just one baby to survive to adulthood? About 1,400.
Just to really hammer this home: researchers safely incubated 6,000 snapping turtle eggs, then released and tracked the hatchlings. Of those 6,000… ONE survived.
And as crazy as the numbers are on that end, they’re just as extreme at the other.
Say we start with 100 adult snapping turtles. How many will die in a given year? Zero.
Two years? Zero. Three years? Zero. Four years? Zero. Five years? Zero. You get it. There is a far less than 1% chance of a given adult turtle dying in a given year. That means if they do, almost impossibly, make it to adulthood? They can pretty confidently expect to live more than a hundred years. How much more? Well, we usually take their age from growth marks on their shell plates, kind of like rings in a tree. But they stop growing after 45 years or so. So we don’t even know how old they get.
So snapping turtles truly live up to their look, as creatures frozen in time. On average: never being born, and never dying.
But don’t let that lull you into a false sense of security. The longevity of snapping turtles needs stability. As you can imagine, any new factor in the ecosystem that ups their death rate throws off this strange and delicate balance. If anything we need to be even more careful with a species for whom each adult member is this much of a miracle.
And you can help with that! Disturbing a snapping turtle nest for any reason is a very bad idea, but if you do find one there are lots of organizations you can call who will come fit them with nest boxes to protect the eggs.
And if you do see a baby turtle trying to make it to a slow-moving body of water with a path or road in the way, by all means help the little guy out. Just be gentle, be quick about it, and try and find a spot to place them in the water with a lot of cover and hiding spots.
If you’re feeling especially brave you can also help adult snapping turtles cross the road too, just, you know, make sure you know what you’re doing. Those necks are a lot longer than you think. I speak from experience.