Could a Maneater be Stalking the Rivers of Iowa & Illinois?

The first "horror" movies I saw when I was a kid were all creature features. The Grizzly, Piranha, Jaws. Those last two may be the reason I am totally terrified of deep or murky water. It's the fear of not knowing what's there with you, lurking just beneath your feet, am I right?

Well, if you’ve ever seen "Jaws," you might be relieved to know that great white sharks prefer the ocean. But what about the shark they think was the actual inspiration for the film? Could the aggressive, adaptable Bull shark really take a Midwest vacation and swim up the Mississippi River to enjoy Iowa and Illinois waters? Let’s dive into the fishy details.

Meet Our Latest Midwest River Monster: the Bull Shark

Aggressive and adaptable, Bull sharks are known for their aggressive nature and territorial behavior, making them one of the shark species most likely to bite humans. But don’t worry—unprovoked attacks are still relatively rare. They're not out to get you without reason anyway. By the way, they're the only known shark (and possible maneater) that can handle fresh water, and that is where things get interesting.

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These sharks give birth to live young, usually in freshwater or brackish environments, which serve as nurseries. A female bull shark’s gestation period lasts about 10 to 11 months, resulting in 1 to 13 pups. The young sharks stay in these safer, food-rich (for their size) waters until they’re ready to venture out to the open sea.

Bull sharks can live up to 16 years in the wild, and even longer in captivity. Female bull sharks tend to be larger, reaching up to 13 feet and 700 pounds, while males are slightly smaller. They have short, flat snouts and broad heads, perfect for ramming prey before taking a bite.

Bull sharks are found in warm coastal waters around the world, from the East Coast of the United States to the rivers of West Bengal, India. They’re even known to inhabit Lake Nicaragua in Africa and the Amazon River, showing off their incredible adaptability.

Food for thought: the Mississippi river basin literally touches or connects to most fresh water systems throughout the Midwest, so maybe a shark sighting isn't so far-fetched. Yes, I am absolutely serious!

Why It’s Possible That a Bull Shark Could Be Found in Iowa and Illinois?

First off, it's already happened! There have been documented cases of Bull sharks in the Mississippi River, including one caught near Alton, Illinois. The one caught there was documented, photographed, and ended up being close to 5 feet in length. That could take a pretty good chunk out of someone.

Some stories talk about a Bull shark being discovered near Davenport. Additionally, 2 Bull sharks were caught and relocated after they were discovered in St. Louis. So, it’s not entirely out of the question for them to venture further north to the waters near Iowa. It makes me think that larger adult Bull sharks are traveling up rivers as a "safe zone" for their young to develop and grow, before heading back to the ocean.

Euryhaline superpowers make Bull sharks the Swiss Army knives of their world. They can live in both saltwater and freshwater, thanks to their incredible kidneys and rectal glands, which help them retain salts and excrete excess water when they’re in freshwater. This euryhaline or salt-tolerant ability means they can hang out in rivers, lakes, and coastal waters. Sometimes indefinitely.

Additionally, Bull sharks aren’t homebodies. They’re known to travel far and wide, sometimes covering up to 200 miles overnight. They’ve been spotted as far inland as the one found in Alton, Illinois—about 700 miles from the Gulf of Mexico. That’s quite the road trip!

Why It’s Unlikely That a Bull Shark Could Be Found in Iowa and Illinois?

While bull sharks are adventurous, they do have a preference for warmer waters. They thrive in temperatures above 69 degrees Fahrenheit. Unfortunately, the Mississippi River around Iowa dips below 35 degrees for months during the winter. A bull shark would find these conditions far from ideal—more like a cold shower than a tropical getaway.

The Mississippi River does have plenty of fish to keep a bull shark well-fed, from carp to catfish. But even the tastiest buffet might not be enough to make them stick around if the water turns icy. They’re likely to head back to warmer waters before winter sets in.

While bull sharks have been seen far upriver, these instances are rare. Most stories of bull sharks in unlikely places tend to be more fiction than fact, like the infamous (and false) tale of a shark in Lake Michigan during the Jaws craze of the 1970s. That being said a shark did attack several people in 1916 in New Jersey, one 15 miles inland in a creek. These attacks became the inspiration for the film Jaws and its subsequent sequels.

Give it to me Straight, are there Sharks in the Mississippi?

While the idea of bull sharks hanging out in the Mississippi River near Iowa is intriguing, it’s more likely to remain the stuff of fish tales. Their adaptability and occasional inland journeys make it possible, but the cold waters of the Midwest are a significant deterrent.

If you were to encounter a Bull shark in our area it would most likely be a pup and no more dangerous than a gar, pike, or muskelunge commonly found in our lakes and rivers.

So, if you’re fishing in Iowa, you’re more likely to hook a catfish than a shark—but it’s always fun to imagine the possibility. And remember, if you ever hear the ominous theme from Jaws while boating, it’s probably just your imagination… or is it?