By Dr. Karen Shaw Becker
Have you ever wondered how alligators survive the winter? Animals have all kinds of tricks up their sleeves, like cloacal respiration, or “butt breathing,” which some turtles use to survive the winter. Alligators, which have been around for so long they’ve been described as living dinosaurs, use another method entirely, which even surprised those at Shallotte River Swamp Park in Ocean Isle, North Carolina.
The Swamp Park is home to 12 rescued alligators that were previously kept in captivity. During an unusual snap of bitter cold that hit earlier this year, record low temperatures were recorded, causing the area’s swamps to freeze, alligators and all. Remarkably, the alligators seemed to know just the right moment when the water was about to turn to ice, and stuck the tip of their nose just above the surface.
The ice froze around their snouts, giving them a portal through which to breathe until the thaw came. The unusual scene is captured in the video above, where you can see the alligators seemingly frozen in place. In reality, they’ve entered a state similar to hibernation, known as brumation.
Alligators Brumate Through the Winter
As cold-blooded animals, alligators depend on their environment to regulate their temperature. When temperatures become too cold, alligators brumate, which is similar to hibernation in that their metabolic rate and other physiological processes slow down.
Unlike hibernation, however, which entails animals falling into a deep hyper-slumber during which they are inactive and do not eat or drink, during brumation alligators become lethargic and stop eating but continue to drink and have periods of activity. According to the South Carolina Aquarium:1
“When alligators brumate … [t]hey cease eating and create mud holes for warmth and shelter. On warmer winter days, alligators will emerge to bask in the sun. Alligators have prominent ridges along their backs called scutes, bone plates that act as a heat conductor.
The scutes contain blood vessels and as the sun warms the surface of the skin, the blood running through the scutes is warmed and distributed throughout the rest of the body, heating the alligator. When an alligator gets too warm while basking, he will open his mouth to dispel the heat.”
Even during brumation, alligators will come to the surface to breathe at least once a day, but, seemingly sensing the swamp was about to ice over, the crafty alligators at the Shallotte River Swamp Park strategically positioned their snouts above the ice, ensuring they had access to air.2 Andrew Grosse, alligator program biologist for the South Carolina Department of Natural Resources, told U.S. News & World Report that he’s also seen this unique survival method:3
"I've seen alligators that have been in ponds that have frozen over … Some of them have adapted to where they'll stick their noses out of the water and let it freeze around them, and they'll stay there until the ice melts."
Brumation usually occurs from November to late February, and it’s actually the changes in daylight — more so than changes in temperature — that signal to animals when it’s time to start preparing for winter. “Both temperature and daylight influence seasonal behavior, but daylight is more consistent,” Grosse said.4 If you see an alligator basking in the sun during the fall, he’s probably trying to soak up as much sun as he can before the winter starts. Likewise if you spot one out during the winter.
Alligators will often sunbathe when temperatures reach the 60s or 70s, and while you definitely shouldn’t approach an alligator no matter what time of year, alligators in the winter tend to pose less of a threat as they’re more lethargic and less aggressive, according to Grosse.5
Alligators Are Survival Masters
The fact that alligators seem to roll with the punches, riding out a frozen swamp with apparent ease, shouldn’t be entirely surprising, considering these reptiles have survived for more than 150 million years.6 Researchers from the University of Florida even state that if you could step back in time 8 million years — and even back 30 million years — alligators would look very much the same as they do today.7 American alligators (the kind in the video above) are not currently endangered, but they’re not invincible.
As recently as the late 1960s, American alligators were nearly hunted to extinction, until they were given protection under the Endangered Species Act. Their numbers have fortunately rebounded, with a wild population of more than 1 million today,8 but they are still vulnerable to several man-made and natural threats, according to the Florida Fish and Wildlife Conservation Commission:9
“The main threat facing the American alligator is the destruction and degradation of its wetland habitat. Destruction of wetlands usually occurs in conjunction with human development. With increased development in their habitat, more alligators are removed at the request of the new property owners; these alligators are usually harvested when removed.
Alligators are also vulnerable to increased predation. Alligator eggs face predation from raccoons, bears, and otters, and juveniles also face danger from wading birds and bigger alligators.”
Most American alligators live in the rivers, lakes, swamps and marshes of Florida and Louisiana, although they can also be found in Alabama, Georgia, South Carolina, Mississippi, Texas and even parts of North Carolina. If you happen to see an alligator, admire it from a distance and don’t feed him; it’s illegal and causes them to lose their natural fear of humans. As for the gators at the North Carolina swamp park, they’re reportedly doing fine after their deep freeze.