Natural History: Southern Leopard Frog

On the rather cool day with no sunshine and the wind blowing, Thursday, March 12, my lab group for Herpetology class embarked on a journey into the freshwater swamps of Caw Caw. While not a prime day for seeing reptiles, the amphibians were numerous as we checked aquatic traps and took our chances at hand-catching in waist-high water and leaf-littered woods. One of the most exciting amphibians that we were all able to see due to a classmate’s amazing capture was an adult Lithobates sphenacephalus (also known as Rana utricularius in some field guides), or commonly known as the Southern Leopard Frog, of the family Ranidae. The first thing that was noticeable was its distinguishable spots that can be seen on its legs and sides, thus the origin of its common name. Round spots were also on its dorsal area, but they are not as easily seen in the pictures. You can also see its characteristic light line along its upper jaw on its long and pointed head. Typically, Lithobates sphenacephalus have a light spot in the middle of their tympanum, but this specimen's was not very light in color, but still can be seen. If I had to estimate its size, I would estimate it was between 1.5 and 2 inches from nose to anus, maybe a bit longer so it was a fair size for its species, which can reach 3.5 inches on average. The dorsolateral ridges or folds extended down to its groin region and its smooth and wet skin made it difficult to hold onto at first. It really wanted to escape to go back into the swamp that it called home, the water being dark and full of aquatic vegetation that it could use for hiding and breeding. It was interesting to see the brown variation that the species is capable of, especially in the swampy habitat that this specimen was captured in where the dark coloration would be useful in the water. Its webbed hind feet were easily seen in comparison to its relatively free toes on the forelegs, the webbing indicating its favor of semi-aquatic environments as the webbing would help it swim. Another thing that was amazing to see was how long its legs were in comparison to its body length! The family Ranidae is known for having long hind legs, but actually witnessing it first hand was very helpful and interesting. I have never been to Caw Caw before our field trip, but after our exciting day, I plan to go back in the future on my own to observe more wildlife in its natural habitat and enjoy the calming walk while listening to the various sounds of the animals that call it home.