Wildlife

Wildlife Wednesday: Northern map turtles “breath” through their skin to survive winter ice

Plus: caribou on camera in Wapusk National Park, black bears take over Yellowknife and large-taloned bird ancestry revealed

Map turtles can only live for a few weeks at a time under the ice. To survive, they need to extract the oxygen dissolved in the water, (Photo: PXfuel)
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What’s that getting into the swim of things under the icy surface of your neighbourhood pond? Well, a northern map turtle, of course!

While snappers and painted turtles can spend several months submerged under the ice with little oxygen, map turtles can only live for a few weeks at a time. To survive, they need to extract the oxygen dissolved in the water.

For years, researchers have observed map turtles wandering across the bottom of icy rivers and lakes. They knew they must be moving for a reason, but why?

They recently fit 40 northern map turtles in eastern Ontario with tri-axial accelerometers (essentially a turtle FitBit) and logged the data. The devices recorded the movement, depth and temperature of the turtles for the seven months they remained under the ice.

The researchers suspect that small amounts of activity may allow the turtles to replace the oxygen-depleted boundary layer of water on their skin with freshly oxygenated water, allowing them to better “breathe” through their skin.

Alternatively, they could just be looking for micro-climates with higher concentrations of oxygen or a preferred temperature or depth.

By better understanding the winter part of the turtles’ life cycle, the researchers will also better understand how climate change may impact these animals.

Capturing caribou

Photo: Parks Canada
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Wapusk National Park in Manitoba is remote, roadless, covers 11,500 square kilometres and  straddles the transition zone between boreal forest, Arctic tundra and the marine biome of Hudson’s Bay. Winters are bitterly cold and summers are soggy. So, when wildlife scientists from the University of Saskatchewan and the Manitoba Métis Federation set out to figure out why the park’s Cape Churchill caribou herd — unique in the way they utilize both woodland and barren ground — was doing better than caribou almost everywhere else in Canada, they had to show some ingenuity. 

The scientists installed 92 trail cameras mounted on posts throughout the park, tackling the terrain on foot to swap out batteries and memory cards at locations close to their Wapusk research camp, Nester One. For the further flung locations, helicopters were called in to service the cameras, including those in an areas where some of the park’s largest polar bears congregate. The caribou herd’s calving range falls almost entirely within the park, so the images could help establish a vital link between habitat protection and population health — something not yet established by science.

The cameras captured images of grizzly bears to Arctic foxes to 25 species of birds and, importantly, they captured thousands of images of caribou. They showed that they weren’t using the park much in the winter, and instead were wintering in forests southwest of Wapusk. Manitoba Métis Federation conservation co-coordinator Riley Bartel hopes to use the data to support the creation of an Indigenous protected area for the herd in these wintering grounds. 

“Their summer grounds are protected,” says Bartel, “but if the wintering grounds could also be protected that just helps preserve this species even more.

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Bears in mind

Photo: Public Domain
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What’s a bear to do? With wildfire approaching Yellowknife at an alarming rate, Aug. 16 saw roughly 95 per cent of the Northwest Territories city’s 20,000 residents evacuated. With only a small number of key workers stayed behind and a whole lot of trash to be rummaged through, reports soon started flowing in of black bears wandering Yellowknife’s streets. Sightings increased steadily in the following days, and video footage was shared by various outlets of bears exploring gardens, walking eerily quiet roads and even chasing a man into a hotel. 

The bears were likely drawn into the city by the trash cans full of waste left behind by evacuees, according to wildlife officers in the area. But the fires also likely played a part, pushing the bears away from their usual territories and toward Yellowknife. The fires also meant the usual method of dealing with bears — using deterrents or catching the bears and releasing them far outside the city limits — became harder to do, and the chances of having to euthanize encroaching bears increased.

The number of bears in the city will now likely decrease as residents continue to return following the end lifting of the evacuation order. Instead they will be forced to take their chances with the still-burning forest nearby.

Get a grip

Photo: Riza Nugraha/Wikimedia Commons [CC BY 2.0]
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Are you talented with your talons? If you’re a bird that answered yes to this question, you probably share a common ancient ancestor.

A study of more than 1,000 species found that all birds — from parrots to raptors — that use their feet for tasks other than perching are part of a large-brained clade of birds known as core land birds or Telluraves (a clade is a large group of species that all trace back to a common ancestor).

The study from the University of Alberta, published in the journal Communications Biology, relied on thousands of pictures and videos shared by birders on the internet.

Some 60 million years ago, the clade’s common ancestor, likely a predator, moved from the forest floor to the trees. The early bird had long back toes that would have worked almost like a thumb for clasping and toe tendons to perch.

The family tree diverged repeatedly through the generations as birds adapted to their diet or surroundings. Birds specialized their footwork for tasks such as holding prey or cracking nuts.

Today, parrots are the most dexterous, followed by raptors. Most songbirds, in contrast, have limited grasping ability or none at all.

Cristian Gutiérrez-Ibáñez, a University of Alberta neurobiologist and the study’s lead author, noted that while it is unclear exactly why each adaptation occurred, various evolutionary pressures, including changes in habitat and diet, were likely at play.

A better understanding of birds’ dexterity may help scientists better understand the evolution of bird brains.

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