Our first field trip took place in mid-February, on a beautiful afternoon when temperatures were in the mid to upper 60s.  On this field trip, we visited several areas within the Francis Marion National Forest just outside of McClellanville, SC.  The Francis Marion National Forest is a 252,368-acre forest in Charleston and Berkeley Counties, South Carolina.  The forest is along the Atlantic Intra-Coastal Waterway. 

The purpose of our field trip was to find local amphibian species.  Most of the areas we visited were along rural, unpaved roads, including roadside swamps and ditches.  We used nets to drag through the detritus at the bottom of the swamps and ditches.  The leaf litter was then examined thoroughly and slowly to maximize the number of species observed.  This allowed us to capture numerous tadpoles as well as some salamander larvae.  We also encountered adult cricket frogs, described below.  We were not successful in finding any adult salamanders on this trip; however, we did find a population of green anoles (Anolis carolinensis). 

Acris gryllus, southern cricket frog

         This individual was found near an area of shallow water along a small road.  We recognized this frog as a member of the tree frog family, Hylidae, by the presence of toepads.  Its small size and small toepads helped narrow down its identification.  and The fact that it was found in the southeast U.S. was the first step in identifying the frog.  Next, its small size helped narrow it down further.  The triangle between its eyes was also a distinguishing feature.  This, combined with its location, allowed us to determine it to be either the northern or southern cricket frog.  Our coastal plain location and the minimal toe webbing helped make the identification final. 

           Acris gryllus can be found in the southeastern United States, from southeast Virginia, into North and South Carolina, and down through Georgia, Alabama, and Mississippi.  These frogs especially like inhabiting shallow ponds, meadows, marshes, coastal plain bogs, and pools along roadsides.  A. gryllus is a small frog that varies in color, but has a characteristic triangular shaped spot between its eyes.  The southern cricket frog is smaller and more slender than the northern cricket frog, its snout is more pointed, its legs are longer, and its toes are less webbed.  A gryllus is important ecologically because it eats insects which often feed on crops.  In order to avoid its predators, including fish, salamanders, snakes, turtles, and certain birds, these frogs can jump long distances or hide using camouflage.  Its call is a rapid clicking that never changes pitch or frequency. 

Anolis carolinensis, green anole

Rana tadpoles

Some members of our class participated in an optional weekend field trip to the Francis Marion National Forest in late February.  We assisted a graduate student from the University of Central Florida who is studying amphibian diversity in the Forest.  The day before our trip, minnow traps had been placed in several shallow wetlands to sample amphibians.  We helped collect the traps and then we got to see all the fun stuff that was trapped.  We caught some fish and crayfish, but the real highlight was catching sirens, which we'd been hoping to see.  They were slimy and wiggly and sooo cool!  We also found carpenter frogs and a variety of tadpoles.

  Out in the cold water of the swamps, collecting minnow traps. We have on our boots up to

  our thighs, and we are sloshing away in the water.  We caught a lot of fun critters this time.

Siren intermedia, lesser siren

After all the hard work of collecting the traps and sloshing around in the swamp, it was time to reap our rewards. This is one of the cool sirens that we found in the minnow traps.

           Distinguishing features of this species include reduced front legs and the absence of hind limbs.  They have four toes on each foot.  Their tail is laterally compressed for swimming.  They are generally dark in color with no markings, but some that are not as dark can have mottled coloration. To distinguish between the two species of Siren, experts suggest counting the costal grooves; greater sirens have more than 36 and lesser sirens have less than 35.  Greater sirens tend to be bigger in size.

            Sirens are fully aquatic, and their habitat consists of swamps, lakes, ditches, ponds and marshes with slow-moving water.  Their range extends from North Carolina down to south central Florida and west to East and South Texas, and north in the Mississippi Valley to Indiana and Illinois.  When the swamps, ditches, and marshes begin to dry up, these salamanders burrow into the mud and, when the mud starts to dry out, they entomb themselves in a kind of cocoon.  It hardens around them and then they “hibernate” until the water comes back. Some stay this way for up to a year, depending on the climate and conditions.

            During the mating season, bite marks can be seen on some sirens. Biting is thought to be part of the courting behavior.  Some females acquire bites from males during courtship.  Males may also have bite marks, which could be due to competition or territorial encounters.  The mating season is dependent on geography. Usually, southern populations breed earlier, with breeding occurring December to March in central Florida and March to April in the Carolinas.  The eggs are deposited in large masses consisting of several eggs, and they are typically attached to submerged vegetation.  The mass may contain from 200 to 700 eggs and hatch within 1.5 to 2.5 months.

Sirens usually prey upon invertebrates, such as crayfish and other crustaceans, insects, snails, worms, and occasionally fish.

Rana virgatipes, carpenter frog

            We captured this carpenter frog inside one of the minnow traps.  We knew this frog was a member of the genus Rana by noticing the large tympanum, typical of the genus.  The tympanum is an auditory organ involved in frogs' hearing.  Then we looked at its back pattern to deduce that it is Rana virgitipes, the carpenter frog.  Four light stripes run down the carpenter frog’s cryptic brown back.  If it wasn’t for the trap, we may have missed it due to its small size and its cryptic behavior.  They can grow up to two and half inches (although ours was a juvenile) and a lack of the dorsal lateral fold.

            The unique call of this frog resembles the popping sound of a hammering carpenter, hence its name.  It also has some webbing on its toes, suggesting its aquatic behavior.  It preys on insects and keeps insect populations down but because it lives in the aquatic environments, it is subjected to predation from water snakes of the genus Nerodia.  The frog’s natural habitat includes the black-water swamps of the Carolinas.  The breeding season of the carpenter frog is usually from March to August and usually spawns hundreds of eggs in jelly. 

Our final  field trip, at the end of March, was to the I’on Swamp Trail in the Francis Marion National Forest.  The swamp trail follows canals that were constructed during the nineteenth century as a means of transportation for plantation owners to transport their rice to nearby Charleston.  These abandoned canals, creeks, and temporary ponds create an ideal habitat for several of South Carolina’s amphibian and reptile species.  Conditions were good for herps, with temperature was in the mid to upper 70s.  Although it was a sunny day, it was still relatively wet in low lying areas due to rain from the previous week. 

We walked along the trail looking for any obvious herps.  Fallen trees were turned over and detritus was shifted through in order to uncover fossorial species, like the slimy salamander described below.  Nets were used to collect leaf litter and detritus from the bottoms of ponds and creeks, which was then searched for amphibians.  However, we were most successful in finding species just by paying close attention to the habitat and looking for any movement. 

Most herps are very cryptic in their habitats.  While this benefits them in their survival, it does make them especially hard to find.  During this field trip, we managed to find representatives from all local amphibian and reptile groups including: frogs, salamanders, turtles, crocodilians, lizards and snakes.  Unfortunately, we were not able to photograph any of the snakes.  One of the species of snake identified was the Easter Garter snake (Thamnophis sirtalis). Two other snakes were not successfully identified.

Clemmys guttata, spotted turtle

Our class found this spotted turtle on our last field trip in the Francis Marion Forest, which is located in the low country of South Carolina.  This was our first herp of the day, and we found it in the middle of the road leading to the I'on Swamp Trail.  Spotted turtles usually establish their habitats near bodies of water such as swamps and ponds; therefore, it was not unusual for us to find this turtle in the road near ditches and other bodies of water.

Clemmys guttata is known for its “polka-dots,” small yellow dots that appear on the carapace, neck, head, and legs.  The background color of the carapace is black, while the plastron is black and yellow.  When spotted turtles hatch, they usually have one dot on each plate of their carapace.  The number of dots may increase with the age of the turtle.  Although the turtle that we found had only one dot per scute, its appeared large enough to be full grown.  Spotted turtles reach 3.5 to 5.0 inches in length.

The spotted turtle’s distribution extends from the southern part of Maine and west to Illinois, and down the coast of the U.S. to the northeastern parts of Florida.  Regions outside the U.S. which have populations of this species include Quebec, and southern Ontario.  The species is considered to be aquatic; however, spotted turtles travel on land as well, especially during mating season when the females make their nests.  Therefore, many of the turtles die from being hit by cars.  Most of these individuals take seven to ten years to mature sexually, and then they can live up to 30 years in age.  The diet of the spotted turtle includes snails, slugs, worms and spiders.  These turtles spend their days basking in the sun and eating.

Spotted turtles are seen anytime between March through October and their breeding season is from March until May.  During courtship, males chase the females around trying to mate.  Several males may fight to mate with a female.  When a female is enticed by the male, she allows him to mount her back and he grabs on with all four feet and puts his tail next to hers and they mate.  Females lay eggs in nests that they dig in meadows and fields.  She lays about three to four eggs and then makes sure to cover up the nest with dirt.  About 11 weeks later her babies hatch.

Plethodon glutinosis complex, slimy salamander

            This salamander was discovered under a log along the I'on Swamp Trail.  Slimy salamanders can be distinguished by its dark throat and black body with many white or brassy spots.  They differ from other dark salamanders living within its range in that it has a nasolabial groove, which is characteristic of members of the Woodland salamander family, Plethodontidae.  There are actually 13 genetically different species of slimy salamanders, but they are all so similar in appearance that they can only be distinguished via laboratory tests.  Slimy salamanders are also called “sticky” salamanders because their skin glands secrete a substance that is very similar to glue.  They grow up to 12-17cm in length, and generally have 16 costal grooves.

            Plethodon glutinosus can be found throughout much of the eastern seaboard of the United States, southward to central Florida and the Gulf coast, and westward to areas of eastern Texas and Oklahoma.  Within its range this salamander seeks out decaying logs in wooded areas and alongside streams and hides underneath stones.  Interestingly, these salamanders can move around underground through burrows made by other animals or insects.  Slimy salamanders breed in early April and eggs are deposited between late spring and late summer, depending on the range.  Females search for moist areas to lay four to twelve eggs.  The hatchlings emerge after approximately three months.  This species is completely terrestrial and the juveniles have no aquatic stage.  All females and most males become sexually mature at the age of two.  During courtship the males will perform a dance and immediately prior to the dance the chin, feet, and white spots on the male will turn pink or bright shades of red.   

            Slimy salamanders are very territorial creatures and show aggression toward any intruder.  Females do everything they possibly can to protect their clutch and even neglect searching for food.  While guarding clutches females are very vulnerable to parasitism by particular nematode worms due to low nutrition.  When foraging for food, slimy salamanders search for ants, beetles, sowbugs, and earthworms.  Plethodon glutinosus has a relatively small activity range, which makes slimy salamanders easy prey for predators such as snakes.

Alligator mississippiensis, American alligator

          We spotted this gator along the I'on Swamp Trail.  This gator was basking in the sun, as they commonly do most of the day to thermoregulate.  It is a young adult, who has likely reached sexual maturity, based on its apparent size.  Alligators are very easy to identify by their broad snout, large teeth and olive green color.  They can be distinguished from crocodiles by their lack of an overlapping fourth lower tooth (gators’ upper teeth all overlap the lower teeth).  However, the American alligator is the only crocodilian native to South Carolina.  Gators are probably the most studied of the crocodilians and are very common in the marshes, swamps, ponds, lakes and rivers of the southeastern United States. 

            Adult male American alligators can reach 4-5 m (20 feet is the largest reported gator) and can eat relatively large mammals.  Alligators are at the top of the food chain and adults face virtually no predators besides humans.  Although alligator population sizes were once critically low, their recovering population (now over 1,000,000) has overlapped with human populations and is the cause of some problems such as eating pets and scaring people.  This is the beast that is infamously responsible for biting off Chubs’ hand in the hit comedy, Happy Gilmore.  In reality, however, alligators usually avoid human contact.  Although they have been known to attack humans if provoked, attacks are uncommon and rarely fatal.  Common places for gator sightings in the southeastern United States include golf courses and other recreational areas with abundant water, where they can be perceived as a “nuisance.”

Sternotherus odoratus, musk turtle

baby alligators, Alligator mississippiensis