Speaking of Nature: the snapping turtle
Bill Danielson photo
Without knowing much about the world outside of their ponds, female snapping turtles just have to go onto land and search for a suitable place to lay their eggs.
Bill Danielson photo
Note that the eye on the left has been seriously injured.
May is a time of new life. Flowering plants begin to seek help from the insects, offering nectar in the hope that the insects will accidentally assist in cross-pollination. Birds, many of whom have just finished migrating great distances, will build nests, lay eggs and perhaps even see those eggs hatch. And for many mammals, the month of May is when new babies are born or when youngsters take their first steps into the world.
For some creatures, however, May can be a very dangerous month. As we humans are driving to work and daydreaming about being free of the responsibilities of our lives and one with nature, there are animals that have to cross the very roads that we are speeding down. Some of these animals are nimble, but others are slow and vulnerable to distracted drivers. Turtles are a perfect example.
It hasn’t happened quite yet, but in the next couple of weeks we are going to start to see turtles crossing the road. Painted turtles are small enough so we might not notice until it is too late, but the largest of our native turtles — the snapping turtle — is easy to see. This does not, however, guarantee that they are easy to avoid. If a turtle tires, or panics, in the middle of the road and stops its progress, it is in big trouble. We’ve all heard the term “sitting duck” used as a metaphor for vulnerability, but I think a “sitting turtle” is in even more trouble.
But when it comes to snapping turtles, there may be more to the story. These are large, predatory animals that will eat just about anything they can grab. Because of their size, there are many things that find their way onto the snapping turtle’s menu, including fish, frogs, snakes, other turtles, mammals and birds. And it’s that last category, the birds, that cause trouble for snapping turtles. Sometimes the birds are adults, but other times they are very young. We have a soft spot for ducklings and goslings and we don’t much care for animals that go around eating them.
So, snapping turtles have a fairly poor reputation in the minds of humans. They are big, “ugly” and they eat animals that we find adorable. Even worse, snapping turtles can be quite aggressive when caught out of the water. They hiss, they open those powerful jaws and they will often make jabs with those long necks of theirs and snap those big jaws shut.
We humans prickle at the effrontery of an animal that is willing to challenge us in such a manner, but if you allow your intellect to chew on this idea for a moment, you might find the hazard of snapping to judgment. Say you’re out for a walk and you are suddenly confronted with a bear. Are you going to just lie down and let nature take its course, or are you going to stand and fight? If you wave your arms, scream, pick up a stick, or throw rocks, are you any different than a frightened snapping turtle?
In addition to being the largest of our native turtles, snapping turtles are also some of the most widespread and abundant. When I was at the University of Massachusetts, a professor once suggested that if you could find a puddle you could probably find a snapping turtle living in it. The trick is that snapping turtles rarely leave the water, so they can go on with their lives virtually undetected. But all of that goes out the window in May, when females have to start looking for places to lay their eggs.
Fish, the oldest of vertebrates, can simply lay their eggs in water. Amphibians, which represent the second stage of vertebrate evolution, have learned how to live out of the water but many species still need to lay their eggs in water. Reptiles, which represent the third great step in the evolution of vertebrates, are finally able to be free of the water altogether. Reptiles lay eggs with shells and these eggs must be kept out of the water, which makes the life of a turtle somewhat ironic.
Imagine a reptile, finally free of the shackles of water, that decides to specialize in aquatic habitats. Suddenly, the need to find dry land for your eggs seems like a really stupid idea, but that’s the reality of the life of a turtle. The burden of this reproductive strategy is not shared equally, however. Male turtles do not need to expose themselves to danger nearly as much as female turtles do. Since the females must lay the eggs, it is the females that take most of the risks.
Snapping turtles, which can live to be 30 years old, may spend several years growing without leaving the water for anything but sunning themselves. Because females must lay eggs, they cannot really breed until their shells are about 8 inches in length. Only then will a female have enough room in her body to carry a full clutch of eggs.
Females need to find soil that is sandy and well drained. This will offer the eggs just the sort of environment that they need: moist, but not wet. I doubt that there is much planning that goes into this activity. When birds migrate they often know exactly where they are going. When monarch butterflies migrate, they show pinpoint precision in their destinations. For a turtle, however, things are probably much different.
Without knowing much about the world outside of their ponds, females just have to go out and explore. Snapping turtles have been found as far as a mile from water in search of a patch of soil that will suffice. Once located, the female will dig a shallow nest with her hind feet and then lay 20 to 40 soft, spherical eggs in to it. Imagine a mushy Ping-Pong ball and you’ve got the right idea. The female will then cover the nest and abandon her offspring to fate.
But fate starts to play its part even before the little turtles hatch. The temperature at which the eggs develop will determine the sex of the young. Soil that holds an average temperature of 68 degrees will produce females. Soil that holds an average temperature of 73 degrees will produce males. Soil with a temperature somewhere in between will produce a mix. So it is possible that the first eggs into the deepest part of the nest will be female, while the last eggs are more likely to be male.
The dangers of this reproductive strategy were brought into focus for me a couple years ago. I was driving home from work and I found a female snapping turtle in a particularly dangerous situation. She was sitting in a section of road that was bordered on both sides with deep ditches. Quite honestly, I don’t know how she managed to get where she was.
I pulled over as quickly as I could, grabbed my camera, and rushed to her aid before she was struck. Snapping turtles have very long necks, so it can be dangerous to grab the front of their shells, but they also have long tails that are easy to grab. If you ever want to move a snapping turtle, the best way to do this is to drag them by their tails.
When I managed to get this female turtle off the road, I took the liberty of snapping a few photos. The trick with animals like this is to get the camera down to their level, which produces a photo that shows their perspective. So I put the camera on the ground and took a few photos without even looking through the viewfinder.
It wasn’t until I got home that I realized the turtle was missing an eye. I was so distracted by the danger of the cars and the possibility of a turtle bite that I completely missed the injury. Suddenly, I was overwhelmed with a wave of sympathy. This female was simply looking for a place to lay her eggs and she was doing so with a disability. I suppose I would be a little grumpy if I were in her shoes, so I couldn’t really blame her for wanting to bite me, could I?
Bill Danielson has worked as a naturalist for 16 years. In that time, he has been a national park ranger, a wildlife biologist and a field researcher. He currently works as a high school chemistry and biology teacher. To contact Bill, or to learn more about his writing, visit www.speakingofnature.com