In between the bouts of rain today, I decided to take myself for a nice little run through Freedom Park. I got onto the Greenway trail right off of Princeton and right about 30 feet away from the street, I came across an Eastern Box Turtle sprinting across the Greenway path. Now, I use the word “sprint” a little loosely, here. I mean, if you’ve ever seen a turtle run, it’s not so impressive. As I got closer, the turtle did stop moving and kept a good eye on me while I watched it.
First of all, Eastern Box Turtles are really attractive turtles. The color patterns on their carapace (shell) are just gorgeous. Since the turtle was stopped, I got a very nice look at it all. As I moved off, I kept an eye on it to make sure that it didn’t get by any cyclists, but I had to move off a reasonable distance before the turtle started moving again. Once it started going, it was really moving. Well, really moving for a turtle, that is. And that observation made me wonder just how fast they actually move. Unlike a lot of animals, turtles have to carry around a lot of weight, so it’s not surprising that they’re not speedy, but just how fast do they move?
Well, in order to talk about turtle speeds, we need to start by pointing out that turtles are ectotherms, which means that external temperatures can play a role in regulating their body processes. As a result, turtle speed is quite temperature dependent, though at temperatures between about 70 and 90 degrees Fahrenheit, their speed is pretty consistent. Outside of that range, speed tends to drop.
It was in the 80’s today (and really humid!), so that turtle should have been at it’s maximum speed. It was however not the biggest of turtles. Do smaller ones move faster because they carry less? Do bigger ones move faster because they’re stronger? Well, apparently, size doesn’t matter in this case. Sprint speeds in Box Turtles is apparently not related to body size. It is, however, related to the number of strides that can make in a given period of time. More strides = faster speeds.
Marvin, G.A. and W.I. Lutterschmidt. 1997. Locomotor performance in juvenile and adult box turtles (Terrapene carolina): A reanalysis for effects of body size and extrinsic load using a terrestrial species. Journal of Herpetology. 31: 582-586.
Ok, temperature makes a difference and body size doesn’t. I still haven’t answered the question! Well, there’s another twist. Slopes matter. Turtles are apparently not very good at walking up steep hills. Is that surprising? Ok, no. It really isn’t. I put it in there, though, in case someone does ask. So this little Eastern Box Turtle kept walking across a pretty flat space on the Greenway, how fast was it going? Well, on a good substrate like that, estimated turtle speeds are about 0.05m/s. That’s 5cm/s. That’s about 2inches/s. In case you were wondering, that’s not fast. Well, unless you’re a turtle, in which case it is pretty speedy.