The Southeastern United States has been hit with a cold front the likes of which it hasn't seen in a long time.
As I try to stay warm inside, my thoughts drift to the wild animals that depend on the temperature outside to regulate their internal temperature, the reptiles. In this area, and Florida in particular, it may get below freezing periodically but it doesn't often stay this cold for this long; and it's becoming difficult for some animals adapted to warmer temperatures.
Lately, there have been many news stories describing the plight of reptiles facing the bitterly cold weather. Some of the particularly entertaining reports describe green iguanas in Florida falling from trees at night and found on the ground in a sort of cold-induced coma the next morning. When brought inside to warm up, these comatose animals gradually regain consciousness. If they had been left outside however, there's a chance they wouldn't have recovered.
Why do these green iguanas seem so poorly equipped to deal with the cold? Sure, it's been colder than usual lately, but it's not so extreme that you would expect mass die-offs of local wildlife. The answer is that green iguanas aren't from the Southeastern United States; they're normally found in Central and South America, where they never had to evolve mechanisms to deal with very low temperatures. The animals we see in Florida are the descendants of released or escaped pets. These iguanas have thrived in the typically warm temperatures and established themselves throughout the Florida peninsula, particularly in the southern portions. In these regions, the climate is similar to what can be found in their native range. One difference, though, is that can sometimes get a lot colder here.
As far as many animals are concerned, the critical difference between the Southeastern United States and more tropical regions isn't that it's hotter in the tropics (although it often is), it's that the tropics don't experience the temperature fluctuations over the year that we do, as the seasons change. It's these temperature fluctuations that the iguanas are unprepared for. There hasn't been a freeze of this type in a few years, enough time for the iguana population to get fairly large, and now we're seeing what happens when they experience weather unlike what their bodies are made for.
It's unpleasant to think of the iguanas dying (a good reason to never release unwanted pets), but it's not considered a conservation concern because they are not part of the native ecosystem. Exotic species in general may wreak havoc on local plants and wildlife and are therefore sometimes the subject of eradication campaigns. Nobody is too worried about the iguanas in Florida; they're doing fine in their native range, where they belong.
On the other hand, some of our very own reptile species are having a hard time dealing with the cold as well. Wildlife rehabilitation centers up and down the coast are being overwhelmed by the number of cold-shocked sea turtles rescued over the last week or so. Unable to function in the cold water, more than 1,000 sea turtles have shut down and floated to the ocean surface, and rescuers have been busy trying to save as many as they can. Although many sea turtles we usually see in the summer probably migrate to warmer waters during this time of year, there are still many that hang around, and these are the animals that are now succumbing to the cold. Most of these turtles probably won't require too much attention at the rehabilitation centers, just a warm place to revive themselves and wait out the cold snap. Still, space and resources are at a premium.
So what, you might say. Sure, it's unfortunate the sea turtles are in trouble, but that's nature's way. Often, I'm inclined to agree with this sentiment, but these animals are highly endangered already and not for natural reasons. Sea turtles, of which there are five species to be found along the Southeastern United States coastline, have lost much of their nesting habitat due to development, been killed by the thousands in shrimp nets and on commercial fishing lines and died en masse by ingesting our garbage (mostly plastic refuse that looks like their jellyfish prey). Together, these threats (and some others) have combined to make their situation a perilous one.
Although they may be facing a natural threat now, our previous actions have put these turtles in a position wherein they are less able to respond to these occasional natural events. Many would argue it's our responsibility to do everything we can to restore sea turtle populations to healthy numbers; I'd be inclined to agree.
David A. Steen can be reached at firstname.lastname@example.org. His columns appear monthly in SouthView.