Understanding Toad Identification

8/11/2020

"Toadal" Overview

Oh, boy... First, I worked on a video with Koaw Nature on YouTube on Toad identification, and it seems to be quite useful. Now, years later, I wanted to make a good literature source for anyone who learns better this way, as well as update and answer some common questions I still get. Still, check out the video. It is linked at the very end of this article. I have spent hundreds of hours on iNaturalist identifying the genus Anaxyrus, and truly, it is not fun... There are thousands of misidentified, poor quality cell phone shots with very few bringing something spectacular to the table. Furthermore, the stream of new misidentified observations is constant. Not to mention these are some of the first species new, learning iNatters post, meaning their observations are riddled with wrong/no locations, duplicates, missing dates, and other common new user issues as well as we have to educate the users on the process, the animals, and often ourselves. I am always excited with the prospects of new iNatters, so I do not mind helping, but it's just a lot on an observation of a misidentified animal. All of that said, I have made it a personal goal, to educate as much on this tangled genus as possible. So, let's explore the truth on these toads and go beyond the field marks to understand our Virginian Toads.

Example of an Eastern American x Fowler's Toad Hybrid | Lunenburg Co. - © Ty Smith

Eastern American Toad | Lunenburg Co. - © Ty Smith

Its NOT Black and White

Toads are hard for most beginning and even intermediate herpers to ID. It is not as simple as how many warts are in a spot like some resources say. Well, if you think you know toads, well have you seen any hybrids? Hybrid toads are rare, but not an isolated incident by any means. In fact, genetic analysis has shown that if you have an overlap in two species in an area, you will have an overlap in genes in that area. This means toad species are highly spectral. Think of it as a spectrum from yellow to red, with all shades of orange in between. Now imagine if I say if it falls in the yellow is Fowler's Toad and if red it is American. This is great, but if you take a point on that spectrum towards the orange middle (A.K.A. pull a Toad specimen from that middle of the spectrum) it would be hard to place it in one category. Generally, I favor calling it what it is most like. It may be an "orange-yellow", but it is still yellow... The reason for this, is sometimes traits of one species will pop-up in an individual of another species, because of an old hybrid ancestor. But sometimes we get a toad that is in the "orange". This meaning, its too in the middle to be one or the other as it is a "true hybrid". In theory, these would be 50%-50% crosses, but in actuality with all toads in a given area having a hybrid in their lineage, meaning the parent is not exactly 100% one or the other, these could be 40%-60% or even 30%-70% hybrids genetically. Personally, if a toad seems more than 2/3rds one species vs the other, I will call it the species it shares the most traits with.

What do I Look for!?

Calm down, we are getting to why you are here. I will now give a synopsis of each field mark, and explain the differences between these species. I will provide many examples of each. I have gotten all of the hard stuff out of the way now, and I will try to keep this next section in more layman's terms. I just wanted to say, toads are tricky because they are a good example of a species that is not black or white. We truly do not have a great definition for what a species is or should be.

Range Maps

Always think about where you are. You probably do not have a toad wildly out of known range. True, we found the furthest west population of Southern Toads in Virginia last year, but this seems to be an exception, due to geography and the little work done with Southern Toads. This is how I define these species.

American: Statewide, excluding the Eastern Shore and the far southeastern corner.
There are NO American Toads native to the Counties/Cities of Virginia Beach, Norfolk, Chesapeake, Accomack, Northampton, Portsmouth, Suffolk, Isle of Wight, or Southampton; and they are seemingly abscent from Hampton, Newport News, Sussex, Surry, and the majority of Prince George (likely present around Petersburg).

Fowler's: Almost statewide, but absent from parts of the Blue Ridge
For some unknown reason there are no iNat records in a huge area that spans from Lynchburg to Abington/Martinsville to Tazewell. Maybe the soils are not as sandy here as they need...? This gap includes Counties/Cities Campbell, Lynchburg, Bedford, Roanoke, Roanoke City, Salem, Martinsville, Franklin, Patrick, Floyd, Montgomery, Giles, Radford, Carol, Pulaski, Wythe, Grayson, Galax, Bland, Smyth, Washington, Tazewell, Russel, and Dickinson. They could still be present and just unreported though, but if so, they still must be fairly rare.

Fowler's Toad | Accomack Co. - © Ty Smith

Southern Toad | NC - © Ty Smith

Southern: Southern Coastal Plain west to Southeastern Lunenburg Co.
Southerns are the least studied of these three, so their range boundaries with Americans seem shaky at best. Southerns are often the most abundant species of these toads in the southern Coastal Plain of Virginia. My belief is they are only present in the Counties/Cities of Virginia Beach, Norfolk, Chesapeake, Portsmouth, Suffolk, Isle of Wight, Southampton, Hampton, Newport News, Sussex, Surry, Prince George, Greensville, Emporia, Brunswick, Lunenburg, York, Dinwiddie, and Williamsburg.

Eastern American Toad | Presumed Range Map

Fowler's Toad | Presumed Range Map

Southern Toad | Presumed Range Map

VHS has some records outside of these ranges, but without personally verifying them, I have to say they are much more likely misidentifications based on the sheer numbers of iNat reports from these areas, with none directly contradicting these ranges.

Dorsal Patterning

American Toads usually have no, or small spots. Forget counting warts per spot, as its an average; look at the general size and shape of each spot. These are often very round or tear shaped. Also, note the larger dorsal warts on the American.

Fowler's Toads rarely lack patterning on the dorsal. They have larger, more irregular blotches and more of them. These blotches look a lot like camouflage blotches, instead of having shape. Fowler's have very few if any enlarged warts.

Southern Toads can be patternless, have small spots, or have large, irregular blotches on their dorsal. With their much more random patterning, it is best to use other methods to supplement this ID. Many will have mildly enlarged warts in large blotches.

Eastern American Toad

Fowler's Toad

Southern Toad

Warting

I mentioned the old "# of warts per spot" adage in the last section. The truth is this "method" is a terrible for ID because it is a side effect of a factor and not the factor. American Toads have enlarged warts and small spots, while Fowler's have big spots and small warts... Meaning, on average Fowler's will have more warts per spot than Americans. Truly old Fowler's will develope some enlarged warting on the dorsal, though its not as common to see these really old specimens. But what about the Southern? Let's not talk about it like it is a third wheel to the party, as it is too overlooked as it is. Southerns tend to have enlarged warts in big, irregular spots; but can have small spots or be patternless. Warting on the tibia/calf of the toad will be the most helpful warting to look at. Fowler's will have equal sized warting on the tibia/calf as that on the thigh. Americans will have several, much larger warts on the tibia/calf. Southern Toads will usually have a few warts on the tibia/calf that are slightly larger than on the thigh (maybe half as enlarged as Americans on average), but not always. Below is a series of photos displaying all of these traits.

Eastern American Toad

Fowler's Toad

Southern Toad

Cranial Ridges

The cranial ridges are a huge tool in toad ID. These ridges are typically "L"-shaped and start between they eyes and run behind the eye. In Fowler's, these ridges are often faint, and run across the top of the parotid gland. Basically, if the cranial ridge was an "L", the bottom line of the ridge will touch the parotid gland. In Americans, there ridges miss the parotid, but sometimes have a spur that points back and touches the gland. Basically, if the cranial ridge was an "L", the bottom line of the ridge will not touch the parotid gland. Adult Southern Toads have ridges similar to the American, but also usually have the presents of cranial knobs. These knobs are tall, horn-like protrusions, that are actually formed on the skull. Young individuals lack these knobs though, but generally their cranial ridges are quite "fluted" between the eyes. I will say many individuals on the northern extent of the range will often have less dramatic or even lack the cranial knobs. It also seems the adult females are the ones with the most prominent knobs.

Eastern American Toad

Fowler's Toad

Southern Toad

Head-shape & Build

Fowler’s Toads have much smaller heads compared to their two counterparts. After seeing thousands of these toads, I have picked up a good enough sense of this to (with Evan and Lindsey as my witnesses) identity toads in the road, from the windshield when cruising. I think the video with Koaw Nature does a great job displaying these side by side. Fowler’s are just so petite compared to the other two species. American and Southerns have these really wide heads, and can grow much larger. Keep in mind these species take a couple years to become full-grown, but odds are if the toad is over 2.5 inches (snout to vent), it is not a Fowler’s. I have seen a few 3 inch Fowler’s, but maybe one a year… and that’s out of several hundred. From the side, I have to say the Fowler’s face looks oddly short as well. Almost like they ran into a wall.

American Toads have longer snouts than Fowler's Toads.

Fowler's Toad showing its short snout

Bellies

The belly, or venter, can be helpful, but only if you really have an idea of what to look for. Generally, Fowler’s Toads have plain bellies with only a “pushpin” in the center of the chest, or faint freckles on the belly. American Toads often have dark spots on their venters. Southern Toads have plain bellies often paler that Fowler’s Toads. This is right on average, but I have seen some exceptions, and the what is faint or dark can be speculative. All that said, I have grown to dislike this way more and more as an ID... See, belly patterns seem more and more like "circumstantial evidence", as below is a clear female Southern Toad that has a very well marked venter. There is a saying in science, "If you say always, you are always wrong." In other words, rely on the sum of a individual's traits and not just one feature to ID.

American Toad Venter

Fowler's Toad Venter

Southern Toad Venter

Southern Toad showing clear knobs, yet a spotted belly from Chesapeake County where there are no naturally occurring or known introduced populations American Toads. Oddly enough this female has a dark chin as well, though it is not as transparent as that of a male.

Southern Toad Tadpoles

American Toad Metamorph Venter

Lifecycle & Dates of Activity

You maybe asking why these two topics are lumped together, but honestly the only good way to ID tadpoles is based on when the adults are breeding. That said, oddly enough the Fowler’s Toad holotype specimen was originally described from a tadpole… but really… Are you going to use a microscope and dissection to ID these tadpoles? All of these species take about 40-60 days to metamorphose into toadlets. American Toads start becoming active and breeding in February. They call and breed until about the middle of April in the non-mountainous regions. In most of the state, Fowler’s begins becoming active in mid April, and calling around the first of May. This means that American Toad tadpoles can be found late February through early May in the non-mountainous regions. While Fowler’s will be active from May onward. Southern Toads however, breed February through September… So, unless you find some early season Southerns, this isn’t really that helpful. Luckily, Southern Toad tadpoles are not solid black like the other two. Southerns are usually mottled black and gold to green. They are not too dissimilarly colored/patterned to Holartic Treefrogs, but they have a clear toad tadpole shape. The biggest exception is the Eastern Shore. Here likely due to lack of competition, Fowler’s breed from February to September, but remember Fowler’s will be the only toad on the Eastern Shore.

Metamorphs are less distinct than the adults, as Americans will have larger spots that break-up with age. Americans will have enlarged tibial/calf warts, but they are not as dramatic. Most American metamorphs will have a "wishbone" shape spot between their parotids. How close the parotid gland id to the eye can help distinguish Fowler's from the other two. The ridges haven't formed, but the spacing for the ridge has. In other words, the parotid in Fowler's is very close to their eye, compared to the American and Southern Toads. Fowler's metamorphs have many more spots, and no enlarged warts. All of these species will have orange foot-pads as juveniles.

American Toad Metamorph

Fowler's Toad Metamorph

Calls

American and Southern Toads have very similar calls as well. One fast “rule of thumb” is Southerns will typically call ~8 seconds while Americans will typically call over 11 seconds. The pitch is a little different in these two species, but it takes some very well trained ears to distinguish, especially when you throw in diversity in vocal range of individuals. Fowler’s Toads have a completely different type of call, which is more of a groan than a trill. Audio of these species can be found on their species profile, and these are linked at the bottom of the page.

But aren’t You Forgetting a Toad..?

Ah, yes… The Oak Toad. Honestly, I went back and forth on if and how to include this species. Truly, it’s is very dissimilar to to other three and I hesitate to call it a similar species. I figured it best to just give it its own section. Oak Toads are tiny, egg-shaped toads with long, spindly legs. In Virginia they are only found in a small section of the Tidewater. They prefer dry, pine/oak forest. They are covered in small warts that don’t really vary in size. They are often a dark, sooty gray with a bold, bright cream stripe down their back. This stripe is far more pronounced than that on the other toad species. They usually have large, black blotches on either side of the spot, and their tall, wide set cranial ridges run between the eyes, but do not hook out towards the legs like the others, but rather back inwards towards each other. So, instead of “_| |_” they are more similar to “|_|”. But if you are really unsure, the venter will solve all of your questions. Oak Toads have mottled venters with orange tubricals on their feet (even as adults) and two orange parabolas around their groin. Oak Toads do not hybridize with the other species.

Oak Toad

Oak Toad Venter

Test Your Understanding

When you find a toad use this guide to make an educated guess. Then post your toad on iNaturalist and tag me @tysmith with a comment like “I believe this is a Fowler’s Toad because of _____.” I will happily look at the toad and answer any questions. All too often someone post an incorrect ID with no explanation to why they think it is that. This means that I really can’t tell you where you went wrong, so you are likely to continue to make the same mistakes. You can also reach out to us on our social media listed in the footer, or use our Herp ID Help Forum linked below.

I also have created a Toad Test to go with this. To really give you an opportunity to use these skills you have learned here. It and our other resources are listed below.