American Toad vs. Fowler's Toad

The American toad (Anaxyrus americanus) and Fowler’s toad (A. fowleri) are closely related, sympatric species of amphibian found throughout much of the eastern United States and Canada. The former species is more abundant whereas the second species is more rare, but they are often mistaken for each other especially on iNaturalist observations. This guide by the Virginia Herpetological Society has always helped me, so I thought I would share it here.

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It is further complicated by the fact that both species will hybridize, particularly in areas where sand dune habitat may be eroding into built-up areas. I have noticed this at one site in the Indiana Dunes area, where I have observed a number of intergrade toads that combine traits of both species.

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Wow, I’m saving the Virginia Herpetological Society website for future reference. Very well done.

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Very useful, thanks. If you want you could add this to the ID wiki topic here: https://forum.inaturalist.org/t/wiki-observing-identifying-wildlife/15332

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Does this apply to toadlets(is that even the right terminology)? So far all my observations of Anaxyrus are at that stage.

Toadlets don’t have developed crests (and I don’t think their belly pattern is developed either), but in my experience the warts-per-spot method works on even the tiniest toadlets. You need to have a reasonably good quality image to see this though.

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Though it seems rare, there are some apparently pure American toads in Canada with more than two warts per dark spot.

https://www.inaturalist.org/observations/20369993

This observation you link to is from the far north of the toad’s range (west side of Hudson Bay). There is only one other observation further north. It is from the east side of Hudson Bay.
These observations also shows more than the usual warts on the dark patch.
https://www.inaturalist.org/observations/56261559 (4 per patch on this small toad)
https://www.inaturalist.org/observations/49779317
https://www.inaturalist.org/observations/55289281
They are from Sudbury, Ontario. In this area, wart numbers per dark patch vary from one to three.

That’s really awesome, thanks! Fowler’s are much more common where I’m from and I always psych myself out about it because typically it’s the other way around so it’s nice to have affirmation.

Thank you for this - very helpful!

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