The Southern Toad (Anaxyrus terrestris) is an amphibian commonly found throughout the southeastern United States. These native toads possess a natural defense mechanism that makes them technically poisonous, a distinction important for pet owners and parents to understand. While the toxicity level of the Southern Toad is significantly lower than that of the invasive Cane Toad, the secretions can still cause serious distress. Healthy adult humans are generally at low risk from casual handling, but the consequences of exposure can be substantial for small children and especially for pets, most often dogs, that mouth or lick the animal.
How Southern Toads Produce Toxins
The Southern Toad is poisonous, meaning the toxins are secreted onto the skin and must be ingested or absorbed to cause harm, rather than being venomous, which involves injection. This defensive poison is produced and stored in specialized glands distributed across the toad’s body. The most concentrated source of the poison is the pair of parotoid glands, which appear as kidney-shaped swellings located just behind the eyes on the shoulders of the toad.
The toxic compound released by these glands is a complex mixture containing bufotoxins, a class of substances that include mild cardiac glycosides. These compounds act as a deterrent, causing immediate irritation and a foul taste when the toad is grabbed or bitten by a predator. The toxin is only released when the toad feels threatened or is physically provoked, such as being squeezed, mouthed, or chewed.
The presence of these bufotoxins means that, while the Southern Toad’s secretions are often described as merely irritating to human mucous membranes, they can still initiate a toxic reaction. In pets, the absorption of these cardiac glycosides through the sensitive mucous membranes can lead to systemic effects. The potency is much lower than the highly dangerous toxins of the Cane Toad, but the risk of oral irritation, profuse drooling, and digestive upset remains a concern for smaller animals.
Identifying the Southern Toad
Distinguishing the Southern Toad from other amphibians in its range is important for assessing potential risk, particularly because of the presence of the much more dangerous Cane Toad in parts of the Southeast. Anaxyrus terrestris is a medium-sized toad, typically measuring between 1.75 to 4.5 inches in length. Its skin is characteristically dry and warty, with coloration that varies widely from brown, gray, or dark brown to a reddish hue, often featuring darker spots.
The most reliable characteristic for identification is found on its head: the Southern Toad possesses two prominent cranial crests, which are bony ridges located behind each eye. These crests run forward and converge near the snout to form a distinct “V” or “L” shape. They also terminate in prominent, enlarged knobs just in front of the parotoid glands.
The geographic range covers the southeastern United States, extending from southeastern Virginia, south through Florida, and west into eastern Louisiana. These native toads are highly adaptable, commonly occupying a wide range of terrestrial habitats including pine woodlands, scrub oak, agricultural fields, and suburban residential areas. They are primarily nocturnal, often seeking cover during the day by burrowing into the sandy soil or hiding under logs and leaf litter.
Immediate Action Following Contact
Immediate action is necessary if a pet, especially a dog, has mouthed or licked a Southern Toad, as the toxins are rapidly absorbed through the oral mucous membranes. The first step is to immediately flush the animal’s mouth with a gentle stream of running water for a full 10 to 15 minutes to wash away the toxic secretion. It is vital to direct the water sideways across the mouth and away from the throat to prevent the animal from swallowing the toxin-laden water, which could lead to aspiration or further poisoning.
A pet that has contacted the poison will often exhibit symptoms such as excessive drooling, pawing at the mouth, retching or vomiting, and inflamed or bright red gums. More severe signs, though less common with the Southern Toad’s milder toxin, can include loss of coordination, tremors, or even seizures. Even if symptoms appear mild, a veterinarian or a pet poison control center should be contacted immediately, as the toxin can still affect the heart and neurological system.
For humans, contact with the toad’s secretions usually results in temporary irritation to the skin or eyes. If the skin is affected, the area should be thoroughly washed with soap and water as soon as possible. If the secretion comes into contact with the eyes, they should be flushed with running water for several minutes. If a small child may have put the toad in their mouth, contact a poison control center immediately, even if the child is not showing severe symptoms, to receive professional medical advice.