When Justin Congdon was a teenager, he spenthis days in the woods of northeastern Pennsylvania, shooting pheasantsand trapping muskrats so he could sell their pelts for $4 apiece. Hewould have laughed had anyone told him he might spend the rest of hislife in a forest preserve trapping turtles, X-raying their bellies, andpainstakingly gluing their shells back together when they had the badluck to be hit by cars.
But that's precisely what he's doingon this late May afternoon at the University of Michigan's E. S. GeorgeReserve, as he has done every spring and summer for 27 years. Carryinga leather tool belt with a makeshift rectal thermometer, needle-nosepliers, and black Sharpie pen, he patrols East Marsh, an 11.5-acrehabitat with water lilies and wild irises. Most of the time he's on thelookout for female turtles— Blanding's, Common Snapping, and MidlandPainted— abundant with fertilized eggs and ready to unload them on thefirst warm day. A low plastic fence separates the turtles' marshlandhabitat from the higher, drier ground where they build their nests. For16 hours Congdon circles the marsh, following the fence that keeps theturtles from escaping. Any gravid— pregnant— female that wants to leavethe marsh must make a small contribution to science before she'spermitted to seek out a place to lay her eggs on the other side of thefence.
He spots a Midland Painted searching for a way pastthe barrier. She has the characteristic bright red trim around theedges of her shell and the intricate lined pattern, almost like a cavedrawing, underneath. He picks her up and pops his thermometer in hercloaca, the chamber in her tail where the digestive, urinary, andreproductive organs come together. She flails her legs wildly and voidswater onto Congdon's hands, but he gets his reading, a useful piece ofinformation for understanding how the turtle manages the heat it needsto carry out reproduction and other biological functions. With theSharpie, he marks her underside, or plastron, with body temperature,time, and location, tosses her into a camouflage-colored bag, andstrides quickly back to his turtle-processing shed, a former militaryradar outpost that has become the border patrol for wandering reptiles.
In this primitive two-room shed, Congdon has conducted some ofthe most sophisticated life-history studies of long-lived vertebrates—research that could upend our theories about how animals grow old andmight one day help unlock secrets of human longevity. For 49 yearsscientists have cataloged more than 12,000 turtles living on thereserve, compiling a huge database of individual reptiles. Each newcapture has its shell marked for identification, and all animals areweighed, measured, and inspected for disease or injury. Gravid femalesare X-rayed to determine how many eggs they're carrying and how bigthey are. Nests are tracked and locations recorded. During peak season,the shed sometimes looks like a turtle traffic jam, and processing cantake until 2 a.m.
