Nature Notes: Slow and Steady

When the fabulist Aesop matched the turtle against the hare in a race two millenniums ago, he must have known something about turtles.

   A week ago Thursday, Stephanie Baloghy, who lives in East Hampton, called to tell me that she had just found a baby box turtle slowly making its way over some leaf-strewn ground in her yard. She examined it as she has examined others in past years. This one had already used up the yolk sack (like our umbilical cord) that is found on the bottom shell of just-hatched turtles. No bigger than a quarter, it most likely hatched last fall but didn’t emerge until a few weeks ago.
    Yesterday, May 23, was World Turtle Day. May is the traditional month for female turtles of both aquatic and terrestrial species to seek out quiet spots in the sun to lay their eggs. In doing so they often cross roads and are easy targets for motorists who are not paying attention.
    When the fabulist Aesop matched the turtle against the hare in a race two millenniums ago, he must have known something about turtles that hadn’t come to light in the world of science until the middle of the last century. Turtles may not move as fast as rabbits, but they outlive them by scores of years. Thus, if the race is long enough, the turtle will always win in the end.
    Before the automobile became the number-one means of transportation in the world, turtles had little to fear in nature. Land turtles, including our own box turtle, are almost impregnable when attacked by would-be predators. That doesn’t mean that none go the way of all flesh, but it takes a mighty weight to crack the shell of a turtle and get at the soft parts. More than 200 million years ago during the very early stages of vertebrate evolution, the emerging tetrapod gave up the notion of getaway speed for the security of a very hard coat of armor, the carapace above, the plastron below.
    Then came another evolutionary change, a two-part plastron with a hinged anterior plate that folded tightly up against the carapace when the turtle wanted to seal itself in. After pulling in its forelegs and hind legs so that all four were safely ensconced inside, it could simultaneously raise up the whole of the hind plate against the overlapping edges of the carapace. A very large carnivorous dinosaur like T. rex could have occasionally crushed a turtle between its jaws, or an elephant or rhinoceros could have accidentally stepped on one, but otherwise, the land turtle’s shell was the epitome of protection against predation.
    Is it the turtles’ slowness of movement or the impenetrability of their shells that enabled the box turtle and the giant Galapagos turtle to live so long, more than 100 years on occasion? (A few such box turtles with shells etched with dates in the early 1900s by the eminent Long Island naturalist John T. Nichols may still exist on the William Floyd Estate, part of the Fire Island National Seashore, in Mastic Beach.)
    There are only a few centenarians among the millions of different animal species extant in the world — crocodiles, parrots, ocean quahogs, humans, tortoises, and, perhaps, a few others. So every time you come across a box turtle crushed by a motor vehicle on the highway, you have to ask yourself: Why, why, why?
    Evolution in vertebrates is a very, very, very long process. It took less than 100 years for Tin Lizzies to evolve into vehicles that can exceed 200 miles an hour on a level stretch of highway. How could a turtle possibly turn around its raison d’etre in such a short time span? It couldn’t; it can’t. In Florida they saved the panthers by installing capacious tunnels under the main highway that coursed through their habitat. The panthers learned to use them quickly. But how many tunnels under, say, Montauk Highway, or Route 114, would it take to save all of the turtles that cross these roads? A lot!
    Species that are fairly well protected against predation tend to have few offspring every time the breeding season comes around. Female land turtles like the box turtle lay as few as four eggs in the earthen pits they hollow out with their hind legs. Aquatic turtles such as snapping turtles, diamondback terrapins, and oceanic turtles lay five or six times that number. Hatchling aquatic turtles are easy targets, especially during their emergence from the nest and trip to the water. Diamondback terrapins and snapping turtles, as well as painted turtles and other Long Island aquatic turtles, get run over, too, but not as frequently as box turtles.
    Turtles have a lot of friends. Various strides have been made to protect turtles crossing roads. Wildlife rescue groups and veterinarians devised ways to save partially crushed turtles using epoxy resins and replacement parts to recondition fractured shells.
    In the mid-1980s, East Hampton Town started a program to reduce the number of box turtles killed on roads. Yellow metallic signs each with a silhouette of a box turtle were put up at strategic points along several town roads. They seemed to have a positive effect, as the number of turtle road kills was reduced thereafter. Instead of blithely running over turtles, motorists began to stop on streets to help turtles cross more quickly, placing them on the other side out of harm’s way.