The Carlisle Mosquito Online

Friday, October 20, 2006


Fowler's toad

photo by Tom Brownrigg
Name. There are 19 genera of true toads and only one, Bufo, is found in our area. Fowler's toad is Bufo fowleri. It used to be considered a sub-species of Woodhouse's toad so it appears in some books as Bufo woodhousei fowleri. Bufo is the Latin word for toad and fowleri refers to the Massachusetts naturalist, S. P. Fowler, who first described this species at a meeting of the Essex Institute on June 30, 1858, based on a specimen collected in Danvers.

When and where seen. Tom Brownrigg saw the toad in the Town Forest on August 21 in a white pine habitat. He sent his photos to Chris Kavalauskas at Oxbow Associates, a company specializing in wetlands and wildlife consulting. Chris confirmed, as best as possible from photos, that this was a Fowler's toad. She cautioned that Fowler's toads can interbreed with the more common American toad and there is a chance that this is a hybrid.

Distinguishing characteristics. A toad is generally easy to recognize because it sports warts. Several factors help distinguish the American toad from Fowler's. While both are blotchy brown and gray with irregular black spots, the proud Fowler's has three or more warts in the black spots while the wart-challenged American has only one or two. Also, in Fowler's there is a distinct white stripe down the center of the back and the belly is white. The American has no stripe or an indistinct one and a speckled belly. Visual aids are simple but if you want to be thorough try the smell test. Fowler's toad is reputed to have a unique smell reminiscent of unroasted peanuts. Comparative toad-sniffing workshops could be arranged next summer if there is an interest. It is possible that a lot of the toads we assume are Americans could be undocumented aliens, Fowler's, or hybrids.

Call signal. The breeding call of Fowler's toad is not anything like the pleasing trill of the American toad. I found several descriptions of it. Audubon Guide: "Like the bleat of a sheep with a cold"; Mass Wildlife magazine: "like a crying, whining baby"; Field Guide to Vernal Pools: "a harsh waaah"; University of Guelph: "a piercing scream."

Fowler's toads breed later in the season than the American toads — from late April through June — so when the American's trilling has died down, if you hear a sheep with a cold you may be listening to the call of the wild Fowler's.

Life cycle. Fowler's toad lays its eggs in gelatinous strands which can be up to ten feet long and contain a double row of eggs in each strand. A clutch has anywhere from 2,000 to 8,000 eggs which hatch in about a week. They take another 40 to 60 days to metamorphose into tiny toads which migrate into woodlands, pastures or gardens usually characterized by sandy soil.

Did you know? True toads have horizontal pupils and no teeth on their upper jaw. They also have parotoid glands on each side of the neck. These glands produce a poison which is an effective deterrent to most predators. The so-called spadefoot toad (genus Scaphiopus) is not a true toad. It has vertical pupils, teeth on its upper jaw, reasonably smooth skin, and no parotoid glands.

References. Leo P. Kenney and Matthew R. Burne, A Field Guide to the Animals of Vernal Pools;; Audubon Field Guide to Reptiles and Amphibians; Richard Wolniewicz, Massachusetts Wildlife magazine, No. 2, 2006.

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2006 The Carlisle Mosquito