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This story was originally published on August 12, 2014

What do sharks and the Great Lakes have in common? The short answer is not much.

Great Lakes fishes come in many shapes and sizes, from the finger-length mottled sculpin to the almost majestic lake sturgeon(below), with its sleek gray torso and angular fins. But don’t confuse this primitive-looking, cartilaginous fish with another group of fishes that have a bit more bite. That is, sharks.

Freshwater lake sturgeon have long, scaleless bodies with ridges along their spines.
Rocks along the south shoreline of Lake Michigan north of the city

You may have heard about a recent “shark tale” that made a big splash in Lake Ontario. The sighting of what appeared to be a large gray fish off of Wolf Island on Lake Ontario was revealed to be a Shark Week hoax.

Still, some shark species have been known to swim in fresh water. Bull sharks, for instance, have evolved to restrict the removal of salt from their bloodstream, allowing them to spend time upriver from coastal areas.

“Every year or two I hear a story about someone finding a shark in the Great Lakes. To date, they have all been hoaxes,” says Phillip Willink, Shedd’s senior fish biologist. Willink said there are fossil sharks from millions of years ago in this region, but the world was very different then. Two hundred and fifty million years ago, a giant inland sea covered what is now the entire Midwest. The Great Lakes are an entirely different ecosystem.

Though bull sharks have been known to ascend the Mississippi River from the Gulf of Mexico as far as St. Louis, Willink says the number of locks and dams as well as the electric barrier on the Illinois River would make it next to impossible for even a bull shark to enter the Great Lakes.

“Every year or two I hear a story about someone finding a shark in the Great Lakes. To date, they have all been hoaxes.”

Phillip Willink, Ph.D.

So, when you’re considering your next dip in the lake, you can have peace of mind that you won’t see any sharks. In fact, the toothiest fish in the lake may be a 3-foot spotted gar, shown here, or a 6-foot longnose gar –both easily recognized by their elongate jaws filled with needle-sharp teeth. 

Feeling nervous about getting in the water with one of these? Not to worry, they don’t attack people, and you can visit them from a safe distance at Shedd’s At Home on the Great Lakesgallery. And spread the word, there are no Jaws in Lake Michigan!

Gar have long, thin bodies with two sets of fins on their bellies for propulsion and steering. Their long, tapered snouts are full of sharp teeth.