Critter Corner No 20 – The Fowler's Toad by George Sly
In previous blogs I have discussed some of the frogs to be found at Goose Pond FWA. During the 2010Biodiversity Survey conducted at GPFWA, eight species of anurans (frogs & toads) were found. In this edition of Critter Corner let’s learn a bit more about the only toad species found during the survey Bufo fowleri. Its name refers to 19th Century naturalist S.P. Fowler who, in 1858, first suggested that this toad was a distinct species. Commonly known as Fowler’s Toad this is the little fellow you often see in your backyard during the summer. As a boy, I often heard this species referred to simply as a “hop toad”.
Toads generally differ from frogs in that the skin of the former is drier, somewhat thicker, and often covered by warty projections in comparison to the thin, moist skin of frogs. The condition of the toad’s skin indicates to us that it spends more time away from water than the typical frog and is thus less likely to suffer water loss via the cutaneous surface. Particularly noticeable on the rough skin of the Fowler’s Toad are two large glandular structures on the head just posterolateral to the eyes. These are the parotoid glands which secrete a toxic substance meant to deter predators. I have seen dogs make the mistake of grabbing a toad in their mouth only to learn that the secretions of these glands make for a very unpleasant experience. Salivating, foaming at the mouth, and experiencing a burning sensation the dog learns a most memorable lesson about henceforth leaving toads alone.
Like the frogs at GPFWA, Fowler’s toads lay their eggs in water where they develop into tadpoles. Toad eggs are laid in strands such as those of the American Toad shown below (L). Frogs (R) on the other hand tend to lay their eggs in clusters.
Of course the reproduction of Fowler’s Toad is, like other anurans, accompanied by loud and prolonged chorusing by the males. Such calls establish their micro-territories and attract females to their location. Fowler’s Toad calls are strange to my ear although pleasant. They have been described variously as bleats, screams, or a loud nasal “waaaaaah”. I suppose a bleating sound might most closely approximate what I hear. Even though the call has range, you must imagine the sound as if it is being made by a Lilliputian sheep of a size appropriate for a set of barnyard animal toys. The spring onset of chorusing by these toads from my neighbor’s pond just over the hill from my house is always a pleasing reminder that longer, warmer days lie just ahead.
Fowler’s Toads are a good example of the animals that we humans often take for granted or ask, “What good are they.” In fact they, like other anurans, are of extreme ecological value. They are important in controlling the populations of their prey species. Insects are the primary targets of toad predation. In addition, and in spite of their toxicity, toads serve as prey for other animals such as Garter Snakes, Hognose Snakes, and raptors. Tadpoles may be eaten by fish and predaceous insects such as diving beetles. Toads are, in other words, important components of what we often refer to as the “web of life” within natural areas.
Interestingly, we may have to begin to think of toads as having practical value for us as well. Today we are finding that the organic chemicals produced by many species of both plants and animals have very significant importance for us as human medicines. Think of vinblastine, a chemical derived from the Rosy Periwinkle, which has increased survival rates for childhood leukemia from 10% to 90%. Among animals, we now use viper venoms as anticoagulants and cone shell venom to produce the drug ziconotide used in the treatment of chronic pain. A recent article in the American Journal of Translational Research pointed out that toad venom has been used as a traditional medicine in Asia for many years. The article suggests that further research by pharmaceutical companies is needed to clarify the efficacy of toad venom in the maintenance of strong heart function, its possible antitumor and antivirus activity, anti-infection effectiveness, and its pain-relieving effects
So, stay tuned. In reference to the toads, the question of “what good are they” may yet yield some surprising answers.
(https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4346519/) (www.sciencedaily.com/releases/2009/09/090924101638.htm) (www.sciencedirect.com/science/article/pii/S1567576910004108)