Scoot over Chance the Snapper: There’s a new famous critter in town. Its name is “Chonkosaurus” and it likes to bask in the sun.

The massive snapping turtle was caught on camera by amateur botanist Joey Santore as it lorded over a Chicago River pylon Saturday. In a widely shared video, the turtle suns itself as its fat, leathery legs burst beyond its shell.

“Look at that beast!” Santore says to the turtle as it rests on rusted chains. “Aye, how ya doin’, guy? You look good!”

The Chonkosaurus moniker came quickly to Santore’s friend upon seeing the “fat and chonky” animal while kayaking near the Division Street Eastern Bridge in the river’s North Branch Canal. The contented turtle appeared to be a pregnant female, Santore told the Tribune on Thursday.

A big but smaller male turtle had been resting with the large lady when Santore first saw it, but scurried away as he got close, he said. Chonkosaurus eventually scampered into the water too, though it took five seconds for the rotund reptile to waddle off the pylon, Santore said.

The botanist, who was filming a video on the river’s plant life for his “Crime Pays But Botany Doesn’t” YouTube channel when he saw the turtle, at first thought the animal was a sandbag. The YouTuber publishes his videos under the Santore pseudonym for privacy reasons.

(Joey Santore)

One social media commenter responded to the video by asking, “Dear lord, what are they feeding that thing?”

“Italian beef,” replied another.

The viral reptile follows in the webbed footsteps of another well-known and surprisingly placed animal, Chance the Snapper, the beloved alligator spotted in the Humboldt Park Lagoon in 2019.

Unlike his alligator predecessor, Chonkosaurus has apparently not yet inspired a series of fan accounts on social media.

[ Our favorite tweets from ‘Chance the Snapper’ and his fans ]

The turtle has lived in the waters around Goose Island for years, said Nick Wesley, executive director of Urban Rivers, a nonprofit organization that focuses on transforming urban waterways into wildlife sanctuaries.

The Chicago River has long been viewed as a dump, “a blight on the city, rather than an asset,” Wesley said. But the beastly turtle is yet another signal of success with efforts to clean the river, including Urban Rivers’ recent work to establish a Wild Mile sanctuary park around Goose Island through cleaning and setting up floating gardens, he said.

“It definitely to me is a good sign,” Wesley said. “The fact that that thing is so fat leads one to believe it has a lot of food to eat.”

Wesley often sees muskrats and beavers in the floating gardens that line parts of the formerly industrial river’s channels. Water clarity is increasing, native fish and mussels are returning, and 101 bird species have been sighted in the river park around Goose Island, including a red-breasted merganser Thursday morning, Wesley said.

The turtles have a few favorite spots, Wesley said.

“It’s crazy to have these giant animals that find this is home,” he said of the massive turtle. “I don’t think it could have picked a better spot to emphasize its girth.”

While some urban animals seem out of place in a big city, Chonkasaurus seemed to belong in the river, Wesley said. Santore said he wasn’t shocked to see a snapping turtle in Chicagoland. He was raised in La Grange and encountered snappers in nearby nature growing up.

“I just didn’t expect to see one at Division Street,” he said.

He can still recall the way the Chicago River smelled when he was a kid: “fragrant,” “odoriferous” and “polluted.” But as he kayaked down the river Saturday, he saw a river recovering, he said.

He went looking for plants and came across pond sliders, ducks and Canada geese. Snapping turtles can tolerate pollution well, but regardless, it’s clear that the river is cleaner than it used to be, he said.

Despite being just blocks from skyscrapers and sliding through waters once notoriously full of trash and toxins, Santore found kayaking on the river to be a way to get closer to nature.

“Slowly, stuff gets cleaned up,” he said. “It’s kinda cool to see it happening.”

jsheridan@chicagotribune.com