Natural History: Anaxyrus terrestris

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Natural History: Anaxyrus terrestris

By: Kyanna Gonzalez

    While at the Francis Marion National Forest on April 4th, 2023, an amphibian was discovered. The amphibian was quickly determined to be a frog due to the morphological features that distinguish it from a salamander or a caecilian. After examining the frog and using the field guide as a reference, it was determined that the frog discovered was Anaxyrus terrestris. Commonly named the southern toad, this frog is considered to be a part of the Bufonidae family due to the frog having parotid glands and warts on its body. The Bufonidae family contains four species; Anaxyrus americanus (American toad), Anaxyrus quercicus (oak toad), Anaxyrus terrestris (southern toad), and Anaxyrus fowleri (Fowler’s toad). Of the four species, there are only two locally in the area and these are oak toads and southern toads. At first glance, the frog was mistaken for an oak toad due to the predominant white mid-dorsal line on its body, a main characteristic of oak toads. After carefully examining the other characteristics of the frog discovered, it was found that the frog was not an oak toad but a southern toad due to the presence of predominant cranial crests. Predominant cranial crests on a toad are considered the key defining characteristic for southern toads as both oak toads and southern toads can have a predominant white mid-dorsal line. In terms of body size, oak toads are smaller than southern toads and the frog discovered was larger than the average size for an oak toad. 

    The form of reproduction and fertilization for Anaxyrus terrestris includes external fertilization where eggs are deposited in aquatic habitats like ponds and wetlands during spring breeding. Females of this species are larger than males but the sex of the frog discovered was not determined. Southern toads are terrestrial and can be found in wetland habitats. While mainly nocturnal, you can find a southern toad catching shade under a log or burrowed in the mud of a swampy habitat. Before being carefully released back to the area it was found, a picture of the southern toad was taken and can be seen attached below.

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