Let’s all learn about Sask turtles because they are so cool
SCIENCE by Gregory Beatty
This story starts with a damn big turtle named Olga.
Last month, University of Regina master’s student Kelsey Marchand and her assistant Alyssa Stulberg made headlines when they discovered the largest painted turtle ever found in North America. The find was made in the initial stages of a two-year research project to study Regina’s wild turtle population — a project funded by the Royal Saskatchewan Museum, Friends of Wascana Marsh, and Wascana Centre Authority.
Olga wasn’t the first chelonian of unusual size the pair has found this year.
“We found one turtle [we] named Houdini,” says Marchand. “She was the first one I thought was going to be a record-breaker. I started doing a literature search to see what the largest western painted turtle was. She was just shy of the record.
“Then Olga came along and took it.”
Olga is a western painted turtle, the largest subspecies of North America’s most widespread turtle. Marchand estimates Olga’s age at 25 to 50 years. Her record-breaking carapace (upper shell) is 26.6 centimetres. The previous record-holder, found in 1922? Its carapace only measured 25.4 cm. Ha! Loser.
What else? Olga represents one of two turtle species native to this province.
“There’s the western painted turtle and the snapping turtle,” says Marchand. “The former’s range goes up to around Saskatoon, while the snapping turtle is primarily on the province’s southern edge.”
With 327 turtle species in the world, you might think we’d have more than two. But turtles are cold-blooded and our climate is generally cool and dry, so it’s no big surprise Saskatchewan isn’t exactly a turtle hotbed.
Still, Wascana Centre provides a decent turtle habitat.
“It’s variable,” Marchand says. “There’s the creek, lake and marsh — which are three completely different [eco-systems]. Turtles love it.”
Olga is proof of that. And when I met with Marchand on July 13, she and Stulberg had just captured their 52nd turtle —a lot of turtles for less than one month into summer — and were measuring and weighing it, taking a blood sample, and tagging it for future identification. The turtle wasn’t large enough to be outfitted with a radio transmitter, but 21 others did meet the size requirement. Marchand is now tracking their movements to see how they use the habitat.
Shell Secrets
This is important research. During the 2004 Big Dig, plans called for excavated dirt to be dumped between two small islands in the lake to make one large island. Fortunately, Friends of Wascana Marsh sounded an alert that turtles over-wintered there and dumping dirt on them would decimate the population.
The more we know about the turtles, you see, the less likely we are to accidentally do something shitty to them.
“One of the main objectives is to determine where they hibernate,” says Marchand. “The hatchlings can either hatch and emerge in late August or early fall, or they supercool and become turtle icicles under the soil and then emerge from the nest in the spring.
“The adults, though, don’t have that ability. They need to find areas that are cold and deep that won’t freeze. Then they slow down their metabolism and literally just chill,” she adds.
Using the radio transmitter, Marchand will be able to check the location of hibernating turtles. Before that, though, she’ll monitor the nests she and Stulberg have discovered to see whether the hatchlings emerge before winter.
“When they emerge is really up to the turtles. If, say, plant roots have infiltrated the nest, they won’t be able to supercool, so they’ll need to get out. Or if there’s bacteria, or ants have come through. Nothing can touch them, otherwise they’ll instantly freeze.”
Marchand’s study can be broken down into three distinct periods in the turtle year. The first ran from spring-time emergence to the first gravid (pregnant) female being discovered.
“That covers the pre-nesting season,” she says. “The nesting season is from the first gravid female until the last known nest is laid. Then there’s the post-nesting season, and hibernation throughout the winter.
Want some more turtle trivia? Marchand says Regina’s turtles are omnivores. “They’ll eat vegetation, water beetles, crayfish — pretty much anything they can wrap their mouth around.”
And with western painted turtles, the gender of the hatchlings is temperature dependent. Warmer eggs in a nest (typically at the top) hatch female, while cooler eggs produce males.
At the 52-turtle mark in the Regina study, females outnumbered males by 10. That’s not necessarily indicative of the total population, though. Because females nest on land, the odds of finding and catching them are greater than with males.
What else? How about speed? Turtles have it.
“Everyone has the impression turtles are slow,” says Marchand. “Those are tortoises. Turtles are actually quite fast. We’ll see them basking, and they’ll be maybe six [of them]. But they can see us coming and will jump off when we’re a kilometre away, so catching them is hard.”
The Big Picture
Marchand’s field study is confined to Regina but the project encompasses the entire province, and she welcomes input from “citizen scientists”.
“If people see turtles, whether they’re western painted or snappers, they can e-mail turtles@royalsaskmuseum.ca,” she says. “If they see one with a number on its back, that’s even better [because] we can tell which individual it is. Submit where you saw it, when, what it was doing, whether it was swimming or up on shore, and a picture if possible.”
Be sure to respect the turtle’s space, though, as the whole point of Marchand’s study is to track their natural movements. Intrusive humans are anything but natural. And pets are trouble too.
“That was primarily during nesting season when the females come up on land to lay their eggs,” says Marchand. “The main thing that would scare them away were dogs coming along. Not many people know turtles are there, but if people can keep their dogs a little closer, especially in the long grass, it would help.”
Exciting Turtle Facts
Turtles are reptiles. Like lizards and snakes, they’re cold-blooded, lay eggs to reproduce, and share certain anatomical similarities — especially skull structure.
One big difference between turtles and other reptiles, obviously, is that turtles have shells. The upper part is called the carapace, while the lower part is the plastron. Recent fossil discoveries suggest turtles date back to the Triassic period around 240 million years ago, and that their shells evolved through the gradual flattening of the ribs and the fusing together of those bones with other bones on the spine and belly.
A hard shell proved to be a successful adaptation against predators, and turtles have existed in their current form for 160 million years. It did require them to develop a different style of breathing than other reptiles, though, which can change the volume of their chest cavities by expanding and contracting their ribs. Instead, turtles use buccal pumping, where they draw air into their mouths, then contract and expand interior muscles to inhale and exhale it from their lungs.
In most turtle species, the shell is covered by a layer of scales called scutes. Scutes are made from the fibrous protein keratin, and as with snakes and lizards, the scutes are periodically shed and regrown.
When turtles are born, says Kelsey Marchand, their shells are soft. That assists their growth to adulthood, but leaves them vulnerable to foxes, coyotes, crows, squirrels and other predators.
“Anything that eats a fish will eat a baby turtle,” she says. “That’s true until their shell hardens, which happens later than people probably think, around four years old. Until then their shells are fairly soft, and they’re a tasty treat.”
One last thing: don’t take the turtles out of the park to make them pets. And for goodness sake, if you have pet turtles, don’t set them loose outside. Three red-eared slider turtles were recently discovered in Wascana Centre, but they’re not native to Regina and were likely pets that had been released into the wild. And that’s something you should never do with any pet. It not only endangers them, but potentially messes with the ecological balance by introducing an invasive species and diseases. /Gregory Beatty
