Alligators are not native to Lake Superior or anywhere else in the upper Midwest. If you see a gator in the cold waters of Superior, you’re probably imagining things.
If you’re short on time, here’s a quick answer: Lake Superior does not have a population of alligators living in its waters. It’s much too cold for these reptiles that prefer the warm climates of the southeastern United States.
In this comprehensive article, we’ll look at details like the climate and habitat of Lake Superior, the native range and habitat preferences of the American Alligator, reported alligator sightings in the region, and reasons why alligators could not survive the winters or establish breeding populations in the lake.
Climate and Habitat of Lake Superior
Lake Superior Geography
Lake Superior is the largest freshwater lake in the world by surface area. At over 31,700 square miles, it covers more area than Switzerland! This enormous lake contains about 3 quadrillion gallons of water and is 350 miles long and 160 miles wide.
Even with its massive size, Lake Superior is relatively shallow, with an average depth of 483 feet and a maximum depth of 1,333 feet.
The lake basin was carved out by glaciers during the last ice age over 10,000 years ago. Situated on the border between Canada and the United States, Lake Superior stretches from Thunder Bay, Ontario in the north to Duluth, Minnesota in the south.
It is fed by over 200 rivers and contains several large islands, including Isle Royale in Michigan.
Year-Round Cold Water Temperatures
One of Lake Superior’s defining characteristics is its consistently cold water. Even in the summer, surface temperatures rarely exceed 55°F. The frigid year-round temperatures are due to the lake’s size, depth, and latitude.
The higher latitude means less direct sunlight to warm the surface, while the size and depth make it resistant to seasonal temperature changes. In the winter, near-freezing temperatures can drop to around 35°F at lower depths.
These cold waters support populations of cold water fish species like lake trout, whitefish, and herring. However, the low temperatures would be inhospitable to reptiles like alligators that thrive in warmer environments.
While alligators have been spotted as far north as North Carolina, they would be unable to survive the year-round frigid conditions in Lake Superior.
Lake Superior Food Chain
As the largest and deepest of the Great Lakes, Lake Superior contains a complex food web. At the base are phytoplankton and algae that sustain zooplankton, insects, and smaller fish. These organisms in turn support populations of larger prey fish like herring, smelt, and alewife.
Top predators in Lake Superior include lake trout, salmon, walleye, northern pike, and burbot. The lake once had a thriving population of lake sturgeon, but numbers have declined due to overfishing and habitat loss.
Bald eagles, osprey, loons, and mergansers are some of the bird species found along the lakeshore.
On land, black bears, grey wolves, moose, and white-tailed deer frequent the forests surrounding Lake Superior. As an apex predator from warmer climates, alligators would not find a place in the Lake Superior food web.
The cold water and lack of appropriate prey species means Lake Superior could not realistically support alligator populations.
Native Range and Habitat of American Alligators
Warm Southeastern Swamps
The American alligator (Alligator mississippiensis) is a large aquatic reptile that resides primarily in the freshwater wetlands and swamps of the southeastern United States. Their native range stretches across the coastal plains and wetlands from North Carolina down through Florida and westward to the southern parts of Arkansas and Texas.
These habitats tend to be warm, shallow bodies of fresh water with abundant vegetation. The alligators thrive in slow-moving rivers, marshes, cypress swamps, and lakes found throughout this region. The lush aquatic vegetation provides ample hiding spots and basking areas for the alligators.
Cannot Tolerate Extended Cold
Although American alligators can withstand seasonal temperature drops, they cannot tolerate extended periods of cold. Prolonged icy weather can be dangerous and sometimes fatal to alligators. This physiologically limits their ability to migrate and establish breeding populations farther north of their current range.
When frigid weather hits, alligators will enter a lethargic state called brumation. Their metabolism slows significantly, so they do not need to eat as much. They will stay submerged with just their nostrils exposed at the water’s surface for oxygen.
Require Aquatic Vegetation for Basking
Access to aquatic vegetation is vital habitat for alligators of all ages. Floating vegetation mats and shoreline vegetation provide essential basking sites for thermoregulation. Adults and juveniles alike will haul out on these sites to soak up the sun’s warmth.
Good water quality and clarity are also critical habitat requirements. Alligators rely heavily on their keen eyesight when hunting. Murky water or dense algae limit their ability to successfully capture prey.
An abundance of fish, crustaceans, small mammals, birds, turtles, and other reptiles in their wetland homes provide nourishment for these large apex predators.
Reported Lake Superior Alligator Sightings
Unverified Rumors
Over the years, there have been occasional reports from locals claiming to have spotted alligators in Lake Superior. However, most experts regard these alleged sightings as unverified rumors or tall tales.
Without photographic proof or other concrete evidence, it’s impossible to confirm whether any gators actually reside in the frigid waters of the Great Lake.
According to the DNR, the climate of northern Minnesota and Lake Superior is far too cold to support an alligator population. These reptiles are cold-blooded and require warm environments year-round to survive.
Nonetheless, some residents relish spreading unsubstantiated stories of encountering gators sunning themselves on the lakeshore.
Misidentified Animals
In many cases, creatures initially reported as Lake Superior alligators likely turned out to be other native animals misidentified by overeager witnesses. Basking logs, swimming deer, otters, and dark shapes in the water can appear crocodilian from afar.
As an illustration, in 2009 a Wisconsin kayaker reported seeing a 4-5 foot alligator in the Apostle Islands area of the lake. However, experts concluded it was most likely a large northern water snake commonly confused for gators.
Without photographic confirmation, misidentification remains the simplest explanation for any alleged stray reptile.
Intentionally Released Pets
Baby alligators do sometimes end up in the north after being purchased as exotic pets. When these creatures grow too large to handle, irresponsible owners have been known to release them into the wild rather than properly re-homing them.
For example, in 2015 a 3-foot alligator turned up near Duluth, MN in the Lester River. Local animal control safely captured what was likely an abandoned pet capable of surviving short summer months but not a harsh Superior winter.
While an intriguing idea, no proof suggests a sustainable population of alligators dwells in Lake Superior. Any verified sightings likely stem from isolated incidents of freed former pets surfacing over the warmer months.
Why Alligators Can’t Survive Lake Superior Winters
Brutal Temperatures and Ice Cover
Lake Superior’s winters are simply too harsh for alligators to endure. While southern U.S. states like Florida and Louisiana rarely drop below freezing, winter temperatures over Lake Superior average a bone-chilling 29°F (-1.7°C) (1).
Frequent Arctic blasts can drive the mercury to -20°F (-29°C) or lower. Thick ice covers up to 95% of the lake by February (2). These frigid conditions would be lethal for alligators within hours.
Alligators are cold-blooded reptiles requiring warm habitats year-round. Once water temperatures drop below 55°F (12.8°C), they become too lethargic to catch food and would soon perish (3). Their metabolism depends on sufficient external heat, which makes survival anywhere with winter ice utterly impossible.
Lack of Suitable Hibernation Habitat
Hibernating through winter isn’t an option either. Alligators can only hibernate by burrowing into the bottom mud of sufficiently deep waters, at least 6 feet (2 meters) below the surface to avoid freezing.
Lake Superior very gradually deepens from shore and has an average depth of 483 feet (147 meters) (4). The broad stretches of shallow water provide no suitable spots for gators to bury themselves.
Additionally, hibernation requires air temperatures to stay above 50°F (10°C) for a portion of the winter, allowing alligators to occasionally rise up for air. The Lake Superior region stays well below that threshold for months at a time. Gators would have no opportunity to breathe.
No Way to Reproduce and Establish Populations
Assuming an alligator somehow managed to temporarily survive Lake Superior’s winter, there would still be no chance for expanding future generations. Alligators require water temperatures of at least 82°F (28°C) for nesting.
Females build nests of vegetation on land near the water’s edge in spring and lay around 40 eggs (5). The eggs would have no possibility of surviving the Midwest’s cold wet springs.
Lake Superior summer water temperatures peak by August at just 55 to 60°F (13 to 15°C) along the shoreline (6). That’s over 20 degrees too cool for gators to breed. And the region simply lacks enough yearly heat for eggs to mature and hatchlings to grow.
Alligators need at least frost-free 200 days per year (7), unlike Lake Superior’s less than 100 frost-free days (8).
Conclusion
While the sight of an alligator in Lake Superior might seem believable after a curious summer visitor snaps a blurry photo, science and common sense show these cold waters are completely inhospitable habitats for alligators.
The next time you hear a far-fetched tale of gators swimming through the icy Superior waters, you’ll know the reality of the situation. Alligators simply do not and cannot live there!
