The Staying Power of Snapping Turtles
Sure, snapping turtles are sometimes irascible and always prehistoric-looking. But these relics, which have been around for 90 million years, are the ultimate survivors.
Snapping turtles, whose jaws are more clamps than guillotines, do occasionally take birds. I found a note online in Volume 108 of The Wilson Bulletin titled "Observations of shorebird predation by snapping turtles in eastern Lake Ontario." The author reports on a turtle that left an inland pond and crossed a sandy beach besieged the whole way by large numbers of angry shorebirds until the snapper entered Ontario and disappeared beneath a floating carpet of algae. Why were the birds riled? In late summer, when lake shallows heat up, large submerged mats of filamentous green algae rise off the bottom and drift. Teeming with invertebrates and small fish, the mats are a floating buffet for migrating shorebirds. Snapping turtles, classic ambush predators, lurk beneath the algae pulling hapless sandpipers through by their feet, an event the author witnessed on three occasions.
Once when I was in northern Virginia, a biologist friend told me of a snapping turtle that grabbed a great blue heron by the leg and then towed the protesting bird into deep water. The turtle sank to the bottom--part anchor, part vise grip--drowning the heron, which it presumably ate. More than 30 years ago, when I was an Audubon biologist monitoring New Hampshire's loon population, residents along the shore of Lake Conway claimed a loon family had lost two chicks down the maw of a snapping turtle. I visited the lake and found several sink-sized turtles sprawled on the surface sunbathing, as though they had bubbled up from the depths like the Lake Ontario algae mats.
To learn about the nesting habits of snapping turtles, I visit wildlife artist David Carroll, whose books include Year of the Turtle and Self-Portrait With Turtles. Carroll is coiffed in gray from chin to crown, casual and energetic, a man who feels deeply about turtles and the fate of their diminishing habitat in the Northeast. When he was 10, he discovered how fast a snapping turtle can strike and how far it can stretch its serpentine neck. An irate turtle opened three of his fingers, although, says Carroll, "I deserved it. I was poking it in the nose with a stick." Undiminished by the experience, Carroll works with state and municipal governments, the Nature Conservancy, and land trusts to preserve critical turtle habitat. A renaissance man who hobnobs with scientists and artists, writers and scholars, Carroll has taught school, plays competitive Wiffle Ball, and has studied the same community of turtles--six different species, including snappers--for more than 30 years. Until he received a MacArthur grant in 2006, he survived on a shoestring with his wife, Laurette, also an artist, producing exquisite watercolor paintings for a series of books.
Carroll takes me to his study site, a sandy pumpkin field at the junction of two streams, a mile from a sizable river in south-central New Hampshire. He prefers not to name the river, because turtle poaching is a serious problem in the Northeast, particularly with wood, spotted, and Blanding's turtles. It's early June, well before noon. The sky is cloudless, the day already cooking. The pumpkin field is warm, a vital consideration for a mother snapping turtle choosing a nest site.
Between mid-May and late June, female snappers disperse upstream from shallow ponds and marshes, sometimes for weeks, looking for well-drained, exposed ground, anywhere the sun hits for the majority of the day--blowdowns, fields, west-facing roadsides, sandbanks and dunes, construction sites, muskrat and beaver lodges. A snapping turtle may even use an ephemeral stream as a route to its nesting site, its shell above the water. Males patrol deeper streams, necks craned, scouting for mates. Territorial disputes between ardent males are cumbersome affairs, and they splash and thrash and shove like aquatic Sumo wrestlers. Several times I've mistaken these battles royal for mating, which Carroll says is more delicate.
At the field's edge are two parallel ridges of sand eight or nine inches long and two or three inches high. A slight depression between them angles downward, and perpendicular to their lower end is the print of a long, well-muscled tail. Eggs lie below the depression. "If you want to see a snapping turtle nest," says Carroll, "go out on a rainy early morning in June." I did that once along a brook near my home and found a turtle leaning out of her little sand pit. She ignored me as I sat there for an hour watching each ping-pong-ball-size egg fall into the pit. Finished, she used her oversized hind feet to spray sand on the eggs, covering the pit, and left for the nearby brook, her personality morphing from oblivious to bellicose, snapping at anyone or anything that might interfere with her return to the safety of water.
I remember that turtle as I look at the pumpkin-field nest and imagine this turtle locked in her own egg-laying trance, skunks and raccoons--the principal nest predators in the Northeast--licking their chops in anticipation of an easy meal. "It's a wonder any eggs hatch," says Carroll, as he points to a pile of eggshells, the remnants of a nest predated a couple of days before.