WHIT GIBBONS’ ECOVIEWS: How old do blanding’s turtles get?

  • Posted: Saturday, June 22, 2013 11:56 p.m.

The captivating Blanding’s turtles are among my favorite turtles in the world. The species is the only native U.S. turtle found exclusively in the northern half of the country and southern Canada--and nowhere in the South. Their farthest excursion southward from Canada is Illinois.

Blanding’s turtles approach the size and shape of a football, but their allure comes not from their physical appearance, a black shell with yellow markings and a bright yellow chin and throat, but their personality. The essence of their charm is their passive nature. Of the hundreds I have seen or handled over the years when I was in Michigan, I have seen only one bite a person, a student named Sue who poked her finger at it. I probably should not have told her that Blanding’s turtles do not bite. But even that one didn’t bite hard enough to hurt. So I still feel comfortable saying that Blanding’s turtles are extremely docile.

Their contemplative gaze is another intriguing trait. Big brown and yellow eyes look right at you, unafraid yet nonthreatening. Looking into the eyes of a Blanding’s turtle makes you wonder if it feels it has chanced upon a recent evolutionary visitor to the world but does not want to be rude or judgmental about your presence.

Young Blanding’s turtles are seldom seen in the wild. Finding one younger than 10 years old is unusual, compared to the number of adults found. The common box turtle is similar in this regard. Think how many full-grown box turtles you have seen crossing roads or wandering through yards, and yet how few young ones you encounter. Blanding’s and box turtles are also similar in having discernible growth rings on the shell that can provide a fairly good estimate of their age. A new ring forms during the cessation of growth in winter, so for the first dozen or so years, you can count the growth rings to estimate how old the turtle is. With Blanding’s turtle over 20 years old, however, the technique is not reliable.

I once caught a baby Blanding’s turtle in Minnesota, one of three I have seen in the wild since I first began studying them 46 years ago. My colleague Justin Congdon who worked with me at the Savannah River Ecology Laboratory has seen more Blanding’s turtles than I have, yet he also has caught only a few little ones. One straightforward ecological mystery for people who study Blanding’s and box turtles: where are the young ones? They are virtually never found with the adults.

Blanding’s turtles live a long, long time. I confirmed their longevity with one I captured, or rather recaptured, in a Michigan marsh. It had been first caught by me 33 years before. According to my earlier field notes, the turtle was an old male when first captured in that same marsh. Blanding’s turtles take around 15 years to reach maturity, and I had judged this one to be 25 to 30 years old when our paths first crossed. When I picked it up more than three decades later, it had the same calm, dreamy look of a younger Blanding’s turtle, but I imagined a spark of recognition in its eyes when it looked at me.

Barring untimely death from automobiles, commercial turtle collectors, and the like, an adult Blanding’s turtle could be around longer than most people. The record for the oldest U.S. turtle of known age ever found living in the wild belongs to a Blanding’s turtle--77 years old! Equally remarkable, it was a female, and when it was found in the late 1980s it was laying eggs. Unless it’s been hit by a car, it’s probably laying more eggs this year.

The last time I returned the old male to the Michigan marsh, it turned its head to look back at me. Its big brown and yellow eyes seemed to say, “I’ll be looking for you next time you visit. I’ll be here.” I sure hope so.

Send environmental questions to ecoviews@gmail.com.

Whit Gibbons is an ecologist and environmental educator with the University of Georgia’s Savannah River Ecology Laboratory.

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