Krochmal Published in “Current Biology”

By Caitlyn Maltese

Elm Staff Writer

For the last couple summers, Associate Professor of Biology Dr. Aaron Krochmal and Franklin and Marshall College professor Timothy C. Roth have recruited teams of student interns to help study local turtles at DuPont’s Chesapeake Farms.  “For the better part of the last five years, my colleague Tim Roth and I, along with nearly 15 students or so, have been looking at the ecology, behavior, and cognition of animals making migrations—particularly turtles,” Dr. Krochmal said.

This month, for their February issue, “Current Biology” featured an image of a turtle on their cover advertising an article written by Dr. Krochmal and Roth. The article titled, “The Role of Age-Specific Learning and Experience for Turtles Navigating a Changing Landscape” is a summary and analysis of their findings.

Their study has the capability to change wild life preservation. It is “potentially of great interest to people who manage wildlife, especially turtles, and that’s a big deal given that somewhere between two-thirds and three-quarters of American aquatic turtles and, in fact, turtles worldwide are endangered. So if we are going to protect them we have to change our strategies because now we know cognitive processes in turtles are limited,” said Dr. Krochmal.

“Classically, on the TV, you’ll see crowds of people taking the delicate turtles and moving them from one pond because we are doing some sort of destructive activity, building a parking lot or a mall,” Krochmal said. “It’s always been billed as a positive thing for the turtles, but now we know that’s decidedly negative because adult animals seem to not be able to learn very much, especially about navigation when they are old. So, we move them to a new place, but they can’t find their way around and they will likely perish.”

They studied how turtles navigate changing landscapes. “What we have learned from this is that animals just don’t walk and get to a new specific place, they don’t wander in circles searching. They actually take very specific, extremely specific paths from point A to point B (from their temporary ponds to a permanent source of water). They do this year after year with exceedingly high precision—among the highest precision movements ever observed in a vertebrae animal that we’ve come across,” he said.

However, after years of study, they have found that not all turtles can do it. “It takes experience to do this right,” said Dr. Krochmal. “They can’t navigate unless they’ve had proper experience as juveniles (within a three year age range— so, between ages one and three, they have experience at this area or else they cannot learn these roots). It is an age-specific experience that will allow them to navigate properly.”

In addition to Giordano, sophomore Erika Koontz, and freshman Nathan Simmons were Dr. Krochmal’s interns this summer.

“We wanted to know, this summer, how age-specific learning impacts turtle navigation and behavior in the wild,” said Koontz.

They had 20 residential turtles from Chesapeake Farms and 20 translocated turtles from Chenio Farms, all of different age groups. They put radio transmitters on them and then released them into one of the temporary ponds at Chesapeake Farms.

“We work with a fairly common system in wildlife management where by temporary water pools are drained annually for wetland management. It’s a very common technique that is largely used for ecological succession of wetlands,” said Dr. Krochmal.

A one-year old turtle fitted with a tracking device as part of Dr. Krochmal’s research.
A one-year old turtle fitted with a tracking device as part of Dr. Krochmal’s research.

Every year the farm invites visitors to hunt waterfowl. Then they have to drain the ponds where the turtles live so that they can seed the bottom of the pond in order to grow grass and create an ideal habitat for their waterfowl.

“This is wonderful for the wetland ecology but not so wonderful for turtles,” said Dr. Krochmal. “But it does open up some opportunity for us to look at how animals navigate from place to place.”

“It’s a simulated environmental catastrophe that happens over the course of a couple hours,” said Koontz.

They tracked the turtles with radio telemetry. Part of the interns’ training included learning how to use the devices. Krochmal would hide transmitters around campus and the student would have to find them.

“It was great. We were practicing on campus, so we would be walking around listening with our ear to this box, having these huge antennas swirling around in our hands,” said Giordano. “Everyone was like, ‘What are you doing?’ We even got some, ‘Are you looking for aliens?’”

So, why turtles? “There are many reasons why turtles are a good model system for the stuff that I want to do—that primarily includes working with students. They are charismatic, but not dangerous,” said Dr. Krochmal, who has been working off and on with rattlesnakes for the last 15 years. During the interview, the molted skin of a massive snake was displayed in the corner of his office draped over a cabinet.

“[Turtles] are accessible…they are, broadly speaking, animals of conservation concern, we know a lot about their behavior, we know a little bit about their cognition and are learning more, and they are fairly common here locally, so, it is a wonderful amalgam of all those spokes on the wheel her. Plus, they are awesome,” he said.

“They are cute, easy to catch, easy to handle, accessible to an undergraduate student. You can get undergraduate students doing topnotch, cutting edge, relevant science on an animal that is not hard to learn about, hard to manage, difficult to catch, scary, or something like that. It’s the best of both worlds for me,” he said.2014 Group

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