[SunkenCiv]

However, it was ascertained that it had perhaps been a bull shark that had made its way up to the lake by way of the Illinois River.

FYI, the Illinois River is a tributary of the Mississippi, and doesn't flow out of Lake Michigan. There's a canal system that in various forms dates back to the mid-19th century, but the system of locks would require patience and planning ability on the part of a hungry shark. Arrival via the St. Lawrence Seaway's Welland Canal -- comprised of eight locks with a total rise of nearly 100 meters -- would have similar requirements.

While not impossible, it seems more likely to be misidentification, or if a shark, perhaps an exotic pet dumping.

[Diana in Wisconsin]

How about a Sturgeon? Do they have teeth? I don’t remember...

[4yearlurker]

Bull shark.

[rdl6989]

I did some digging and I found this article with more info:

https://www.wglt.org/post/getting-bottom-lake-michigans-legendary-shark-attack

[mass55th]

I’ve read about Bull Sharks being found in the St. Lawrence River.

[dfwgator]

Candygram!

[John S Mosby]

Would have to be a shark that tolerates fresh water, and also different oxygenation levels of fresh water. Sharks do not have moveable gills, and so.... MUST swim to drive oxygenated water over their gill rakes.

Secondly the imbalance of less saline content in the water would drive the saline out of the shark’s system, and eventually kill it.

So I agree with a bull shark— most common seen in brackish canals and such. Or a damn huge catfish (the big ones could take a leg if they wanted to— key is photos of bite marks- a catfish would tear the leg off. There are huge ones in the TN river hanging out near dams.... human eating size have been seen, rarely caught.

[piasa]

There was a bull shark caught at Alton, Illinois, just north of St. Louis, on the Mississippi.

And there is an ancient prehistoric Indian city across from St. Louis where mostly decayed clubs/”swords” of wood with real shark’s teeth along with flint points made in the shape of shark’s teeth still mounted in the handles, were found during archeaological digs. They had copper clad hanI think one was plowed up, too.

[piasa]

There was a bull shark caught at Alton, Illinois, just north of St. Louis, on the Mississippi.

And there is an ancient prehistoric Indian city across from St. Louis where mostly decayed clubs/”swords” of wood with real shark’s teeth along with flint points made in the shape of shark’s teeth still mounted in the handles, were found during archeaological digs. They had copper clad hanI think one was plowed up, too.

[They weren’t fossilized shark’s teeth, either]

[dontBSme]

Large Muskie?

[piasa]

Bilgewater dump from a seagoing vessel?

[central_va]

Thankfully it wasn’t a land shark.

[catnipman]

“The Mysterious Shark Attack in Lake Michigan”

thank goodness this was before lasers were available ...

[heavy metal]

sharknado...

[golux]

PS Excellent new GWS shark film if you haven’t seen it.

https://www.pbs.org/video/great-white-shark-new-perspectives-of-an-ancient-predator-zidgxv/

[ThanhPhero]

Some sharks can tolerate fresh water for a lengthy span and sharks have been caught or sighted in Peru in the upper reaches of the Amazon. They do rarely enter rivers and go long distances. I wouldn’t think they could get past dams and waterfalls but ...

[ConservaTeen]

Interesting..a shark in Fresh water?? Could they survive in lakes?

[Darksheare]

You know anything about this?