The question of whether “black toads” are poisonous involves a biological truth about all toads and a critical misidentification of a highly toxic species. All toads belonging to the family Bufonidae secrete a defensive poison, but the danger level varies drastically. These poisons, collectively known as bufotoxins, are complex chemical compounds used to deter predators. The toxicity is not a venom delivered through a bite, but rather a milky, irritating secretion released when the toad is stressed or attacked.
The Universal Truth: All Toads Secrete Toxins
The defensive toxins are produced and stored in glands located throughout the toad’s skin, most notably in the large, bulbous parotoid glands situated behind the eyes. When a predator, such as a dog or cat, mouths or bites the toad, pressure on these glands causes the rapid expulsion of the toxin. These secretions are rich in bufadienolides, which affect heart function, and tryptamine-related substances that act on the nervous system.
Toxicity occurs when the poison makes contact with a predator’s mucous membranes, such as the lining of the mouth, the eyes, or the gums, allowing for systemic absorption. While milder toad species might only cause intense irritation, excessive drooling, and vomiting, contact with highly potent species results in a medical emergency. This defensive mechanism is why toads have warty, dry skin, differentiating them from the smooth, moist skin of most frogs. The severity of poisoning depends entirely on the toad species, the amount of toxin absorbed, and the size of the exposed animal.
Differentiating the Black Toads
The term “black toad” is confusing because it refers to both a rare, native North American species and a common, highly dangerous invasive species that can be dark in color. The true Black Toad (Anaxyrus exsul) is an extremely restricted species found naturally in only a few spring systems in Inyo County, California. Like all toads, it secretes a defensive poison, but due to its highly localized and protected habitat, it is not the primary threat to pets or people in most of the country.
The severe threat comes from the Cane Toad (Rhinella marina), which can appear very dark, even black, especially when wet or young. This invasive species is a major concern in warmer regions of the United States, including Florida, Texas, Louisiana, and Hawaii. Cane Toads are significantly larger than most native species, capable of growing up to nine inches long. They possess very large, prominent parotoid glands that are triangular and extend over the shoulder. These massive glands and a distinct bony ridge over the eyes distinguish the Cane Toad from less toxic native species.
The Severe Threat of Highly Toxic Species
Exposure to the Cane Toad’s poison constitutes a life-threatening veterinary emergency due to the potent nature of its bufotoxins. These toxins include cardiotoxins, which affect the heart, and neurotoxins, which target the central nervous system. For pets, particularly dogs who mouth toads, the effects are immediate and severe.
Initial symptoms include profuse, foamy salivation, gagging, pawing at the mouth, and the sudden appearance of bright red or “brick-red” mucous membranes in the mouth. Within minutes, the systemic effects of the neurotoxins and cardiotoxins begin to manifest. An exposed animal may experience loss of coordination (ataxia), muscle tremors, vomiting, and disorientation. The poisoning can quickly progress to seizures, cardiac arrhythmias, breathing difficulties, collapse, and death, sometimes within 15 minutes of exposure.
Immediate Action and Emergency First Aid
Immediate action is necessary for any suspected toad exposure, especially where the Cane Toad is established. The first step is to immediately remove the unabsorbed toxin from the animal’s mouth and gums. This is done by wiping the mouth thoroughly and repeatedly with a wet cloth or towel, or by rinsing with a gentle stream of water.
When rinsing, direct the flow of water sideways, out of the mouth, and never down the throat, to prevent the animal from inhaling the water or swallowing the toxin. Once the mouth is flushed, the pet must be rushed to an emergency veterinary clinic, even if it appears to recover quickly. Supportive care will be required, including IV fluids, heart rhythm monitoring, and medication to manage neurological effects. Preventive measures, such as keeping pets on leashes at night and eliminating outdoor water sources where toads congregate, are the best defense.