by Greg Mayer
These photos were submitted by Leo Zaibert, who came across this turtle while out for a walk near his house in upstate New York, which is close to the Mohawk River. He was very impressed by its size and prehistoric demeanor, and surmised it was a snapping turtle (Chelydra serpentina), which indeed it was.
It was crossing the road, heading toward the Mohawk, which Leo estimated to be about 100 yards away. At this point along the Mohawk the river is bordered by wetlands, which is probably where snapping turtles in the river would spend most of their time. The turtle stopped as Leo approached, assuming a more defensive posture. In the water a snapper will run away, but on land they raise and direct their shell toward a threat, and will bite. There are good summaries of snapper biology available on the web by the Virginia Herpetological Society and the Savannah River Ecology Lab, and for the truly dedicated a monograph edited by Anthony Steyermark, Michael Finkler, and Ronald Brooks (2008).
This is a large adult. My guess is that it’s a female out looking for a nesting site. They need diggable soil in an area that won’t flood, so they need to be a few feet (at least) in elevation above the level of the water body they live in, and this can lead to them wandering along the roads, and even digging nests sometimes in the unpaved shoulders on the side of the road. In many turtles females are bigger than males, but in snappers males are larger. You can see a fairly luxuriant growth of algae on the snapper’s carapace, which is fairly typical. The algae has dried a bit, as the turtle has probably been wandering around on land for a bit.
Leo estimated its size at 40 inches, but I think this is an overestimate. The size of a wild animal, especially a bulky one like a snapper, is often overestimated, but this is not so much an error as a reaction to the unexpected appearance of an impressive beast. Snappers have big heads, long necks, and long tails, which adds to the impression of size: the tail is a bit shorter than the shell length, and the extended neck is quite long too, so that the total length of a snapper is well over twice the shell length.
My fairly large snapper (I went up to my lab and measured after getting Leo’s photos) is 10 3/8 inches straight line in the midline shell length, 8 inches tail length (the tip was infected and fell off many years ago, so would probably be about 8.5 inches), and the neck and head stretched out 7 inches toward my finger, but could probably reach a few inches more (I didn’t want my finger close enough to actually elicit a strike!), for a total length of 25+ inches, but less than 30 inches. A really big snapper would be about 14 inches in shell length, which would be about 35 inches total including neck and tail. (The record shell size for the species is 19 inches, which would make it over 40 inches in total length.)
Big snappers are very impressive beasts; at the Virginia Herpetological Society page there’s a photo of a guy holding an 18 inch shell (the state record) that shows how really large they are. There’s a species down south, the alligator snapping turtle (Macrochelys temminckii), that gets much bigger: up to 31 inches shell length, and over 200 lbs.!
Leo, who wished it to be recorded that he is a “noted expert on herpes or something”, is a philosopher, and reported that on a previous gallivant along the banks of the river that he miraculously emerged from the “treacherous quicksand of the Mohawk”, though I suspect it was deep mud, myself.
Steyermark, A.C., M.S. Finkler and R.J. Brooks. 2008. Biology of the Snapping Turtle (Chelydra serpentina). Johns Hopkins University Press, Baltimore. JHU Press