Temperature Influences Alligators

Temperature affects all living things in some way.  This is especially true of alligators.  While exploring the wetlands of South Carolina last week, I became much more aware of how ambient temperatures drive almost all aspects of their lives.

As cold-blooded reptiles, alligators are ectothermic.  They rely on external sources to regulate their body temperature.  For example, they lay out in the sun to warm up and float in water to cool down.  Temperature also affects an alligator’s ability to eat.  As temperatures decrease, so does its metabolism.  In fact, when temperatures fall below 70°F they stop feeding since they will not be able to digest what they consume.  If temperatures fall even further, into the 50°F range, alligators become inactive or dormant and ride out the colder weather in dens.

Environmental temperature also plays a critical role in determining the gender of baby alligators.  Through a process known as temperature-dependent sex determination (TSD), eggs that incubate at 93°F or higher all become males while temperatures below 86°F produce all females. Temperatures that hover in between create a mixture of both sexes. Scientists do not know exactly why this process developed, but they have found that it tends to produce more females than males.


An alligator basks in the sun along the edge of a swamp in South Carolina.

Image Credit: The Weather Gamut

Floods Nurture Congaree National Park

Floods are often thought of as disasters, especially when people and property are harmed. In nature, however, some ecosystems thrive on periodic flooding. While traveling in South Carolina last week, I had the opportunity to visit one such place – Congaree National Park.

Situated in the floodplain of the meandering Congaree and Wateree Rivers, the park protects the largest expanse of old growth bottomland hardwood trees still standing in the southeastern United States.  It is home to a dazzling array of biodiversity, including a number of champion trees – tress that hold the size record for their species.  These include a bald cypress with a circumference of twenty-seven feet and a loblolly pine standing one hundred seventy feet tall.  These trees would not be able to flourish without the moisture and nutrient–laden sediments that flood waters bring to the forest floor.

This floodplain forest is typically inundated by water several times a year. During my visit, the park was about 90% flooded as a result of recent heavy rainfall on top of an already wet spring.  It was an impressive sight.

The elevated boardwalk trail in Congaree NP disappears into high flood waters.

The elevated boardwalk trail in Congaree NP disappears into high flood waters.

Image Credit: The Weather Gamut