The Green Frog and American Bullfrog looks the same but the Bullfrog lacks a dorsal ridge down their back. The American Bullfrog also grows much larger than the Green Frog.
The Northern and Southern Leopard Frogs look extremely alike. The Southern Leopard Frog has a white spot in its tympanum (ear spot) while the Northern one generally doesn’t. The Northern Leopard Frog has a more rounded spot than the Southern Leopard Frog.
The Eastern and Gray Tree Frog and the Cope’s Gray Tree Frog are identical besides their calls. They have yellow markings on their hind legs. They can also be green or gray in color.
The True Toads are your typical toad. They usually have a parotid gland behind their eyes that contain a poison called It is not advised to let your dog eat these guys.
The American Bullfrog is the largest native frog in the United States. There is no dorsal ridge that runs down its back on the American Bullfrog. This is the distinguishable characteristics of the frog.
The Green Frog looks very much like the American Bullfrog but it’s a tad smaller. It has a dorsal ridge that runs down its back but they are incomplete and do not reach all the way.
The Lowland Leopard Frog is stockier and paler than the Northern Leopard Frog.
Relict Leopard Frog (Rana onca)
The Relict Leopard Frog hasn’t been seen in the state since the 50s so it is probably extinct but who knows. The dorsal folds on the frog end well before the groin. It also has shorter legs than the Northern Leopard Frog.
The American Bullfrog and the Green Frog are similar but the American Bullfrog is larger. The Green Frog also has a impartial dorsal ridge while the American Bullfrog does not have one.
Pickeral Frog, Northern Leopard Frog, Atlantic Coastal Leopard Frog look very similar to each other because of the spots but the Pickeral frog’s spots are more rectangular than the Northern Leopard / Atlantic Coastal Frog. Now for Atlantic Coast Leopard Frog vs Northern Leopard Frog, the Atlantic Coastal Frog has more white in its tympanum than the Northern.
The True Toads are your typical toad. They usually have a parotid gland behind their eyes that contain a poison called It is not advised to let your dog eat these guys.
Gopher Frogs have irregular spots all over their body and their skin is rough. There are only two records of the frog in the state so its not likely to be seen.
The Cricket Frogs look really similar but there’s a few ways to tell them apart. The Southern Cricket Frog has a more pointed snout while the Northern Cricket Frog has a more blunt snout. The Southern Cricket Frog doesn’t have as much webbing on the back legs as the Northern Cricket Frog.
These two frogs are identical besides their calls and chromosome numbers. These tree frogs are also larger than the ones below. Also note that Gray Tree Frogs are not always gray and can be green. These frogs also have orange or yellow markings on their back legs.
The Eastern Spadefoot Toad is the only species of spadefoot toad in the state. They have a noticeable spade on their hind legs that they use for digging.
The Northern and Southern Leopard Frog look very much alike with their uninterrupted dorsal ridges and spots but there are some differences. Southern Leopard Frog has a white spot on the tympanum and has a more pointed snout.
The Plains Leopard Frog looks like the Northern and Southern Leopard Frog but the dorsal ridge is not complete like theirs. It shifts inward near the groin and can be broken.
These two frogs are identical besides their calls and chromosome numbers. These tree frogs are also larger than the ones below. Also note that Gray Tree Frogs are not always gray and can be green. These frogs also have orange or yellow markings on their back legs.
Here is a video of some Eastern Gray Tree Frog males calling that I took
The Crawfish Frog gets its name from living in crawfish holes. Its has skin folds on the side and a small typanum. It also has a pair of vocal sacs for calling.
The American Bullfrog is the largest native frog in the United States. There is no dorsal ridge that runs down its back on the American Bullfrog. This is the distinguishable characteristics of the frog.
The Green Frog looks very much like the American Bullfrog but it’s a tad smaller. It has a dorsal ridge that runs down its back but they are incomplete and do not reach all the way.
The Southern Leopard Frog has a white spot on its tympanum which can help differentiate the species from the other two. The Plains Leopard Frog is different from the Southern and Northern Leopard Frog because of its dorsal ridge. The Plains Leopard Frogs has a break and an indent near its butt while the North and South Leopard Frog just has a straight line.
The Northern Cricket Frog is the only cricket frog in the state. Its skin is relatively more rough than the other tree frogs in the state. It also has no distinct markings.
These two frogs are identical besides their calls and chromosome numbers. Note that Gray Tree Frogs are not always gray and can be green. They have yellow or orange coloration on their back legs which is nice to identify them.
Here is a video of some Eastern Gray Tree Frog males calling that I took
The Upland and Cajun Chorus Frog are both found in the Southeast part of the state. They are very hard to tell apart. The best way to tell is by their calls and through genetic testing. The stripes on their back are often broken and can even appear as spots.
Illinois Chorus Frog
The Illinois Chorus Frog does not have a white line that extends off the lips while the other chorus frogs do.
The Fowler’s and Woodhouse’s Toads both have cranial crests that form opposing L shapes. The Fowler’s Toad has largest, dark spots on its back that have 3 or more warts in them.
The Great Plains Narrow Mouthed Toad is found on the western edge of the state. It has a light, unmarked belly and has no patterns and a few spots on its back.
The Plains and Southern Leopard Frog can be hard to tell apart. The Southern Leopard Frog’s dorsal ridge down their back is unbroken while the Plains dorsal ridge can be broken.
Pickeral Frog and the Leopard Frogs look very much a like. The Pickeral Frog has more square shaped spots on its back while the Leopard frogs has more circular ones.
The Northern Cricket Frog is the only cricket frog in the state. Its skin is relatively more rough than the other tree frogs in the state. It also has no distinct markings.
These two frogs are identical besides their calls and chromosome numbers. These tree frogs are also larger than the ones below. Also note that Gray Tree Frogs are not always gray and can be green.
Here is a video of some Eastern Gray Tree Frogs calling that I took.
The Gray Tree Frogs and the Bird-Voiced Frog look very much a like. The difference is the coloration on the inner thigh. The Gray Tree Frogs have brighter orange color on the thigh while the Bird-Voiced Frog is more greenish-yellow.
Cajun Chorus Frog has three stripes that run down its back that are often broken up and can appear as spots.
Strecker’s Chorus Frog (Pseudacris strecker)
The Strecker’s Chorus Frog lacks doesn’t have any pattern of stripes or dots on its back. It has a line that runs through its eye and down its side though.
Spotted Chorus Frog (Pseudacris clarkii)
The Spotted Chorus Frog obviously has spots that are green and are bordered by black.
The Fowler’s Toad appears similar to the American Toad. Their postorbital ridge touches their parotid gland. They also have a white belly while the American Toad’s is speckled.
The Crawfish Frog gets its name from living in crawfish holes. Its has skin folds on the side and a small typanum. It also has a pair of vocal sacs for calling.
The American Bullfrog is the largest native frog in the United States. There is no dorsal ridge that runs down its back on the American Bullfrog. This is the distinguishable characteristics of the frog.
The Green Frog / Bronze Frog looks very much like the American Bullfrog but it’s a tad smaller. It has a dorsal ridge that runs down its back but they are incomplete and do not reach all the way.
The Southern Leopard Frog and Plains Leopard Frog appear identical. They both have large spots all over their body. The difference between the frogs lies in their dorsal ridge. The Southern Leopard Frog’s ridge runs straight down the side while the Plains Leopard Frog’s ridge indents near the butt.
The Northern Cricket Frog is the only cricket frog in the state. Its skin is relatively more rough than the other tree frogs in the state. It also has no distinct markings.
These two frogs are identical besides their calls and chromosome numbers. These tree frogs are also larger than the ones below. Also note that Gray Tree Frogs are not always gray and can be green.
Here is a video of some Eastern Gray Tree Frog males calling that I took
The Boreal Chorus Frog has three lines that run down its back and are rarely broken up but if they are, its usually only the middle stripe.
Strecker’s Chorus Frog (Pseudacris strecker)
The Strecker’s Chorus Frog lacks doesn’t have any pattern of stripes or dots on its back. It has a line that runs through its eye and down its side though.
Spotted Chorus Frog (Pseudacris clarkii)
The Spotted Chorus Frog obviously has spots that are green and are bordered by black.
The Fowler’s and Woodhouse’s Toads both have cranial crests that form opposing L shapes. The Fowler’s Toad has largest, dark spots on its back that have 3 or more warts in them.
The Eastern Narrow Mouthed Frog’s range barely reaches the southeastern corner of the stateIt has a dark belly and often has a broad line down its back.
The Crawfish Frog gets its name from living in crawfish holes. Its has skin folds on the side and a small typanum. It also has a pair of vocal sacs for calling.
Common Name: American Bullfrog Scientific Name: Rana catesbeiana Location: Throughout state Breeding Season: April to July
The American Bullfrog is the largest native frog in the United States. There is no dorsal ridge that run down the back of the American Bullfrog. Males of the species have a yellow throat while females have a white throat.
Common Name: Bronze Frog or Green Frog Scientific Name:Rana clamitans Location: Throughout state Breeding Season: April to July
The Green Frog looks very much like the American Bullfrog but it’s a tad smaller. It has a dorsal ridge that runs down its back but they are incomplete and do not reach all the way. Males of the species have a yellow throat while females have a white throat.
Common Name: Southern Leopard Frog Scientific Name:Rana sphenocephalus Location: Throughout state Breeding Season:
The Southern Leopard Frog and Plains Leopard Frog appear identical. They both have large spots all over their body. The difference between the frogs lies in their dorsal ridge. The Southern Leopard Frog’s ridge runs straight down the side while the Plains Leopard Frog’s ridge indents near the butt.
Common Name: Cope’s Gray Tree Frog Scientific Name:Hyla chrysoscelis Location: Everywhere besides the northwest corner of the state Breeding Season: March to August
These two frogs are identical besides their calls and chromosome numbers. Note that Gray Tree Frogs are not always gray and can be green. They have yellow or orange coloration on their back legs which is nice to identify them.
Common Name: Bird-Voiced Tree Frog Scientific Name:Hyla avivoca Location: Southern edge of state Breeding Season: April to August
The Cope’s Gray Tree Frog, the Eastern Gray Tree Frogand the Bird-Voiced Frog look very much a like. The difference is the coloration on the inner thigh. Cope’s Gray Tree Frog and Gray Tree Frog has brighter orange color on the thigh while the Bird-Voiced Frog is more greenish-yellow.
Common Name: Squirrel Tree Frog Scientific Name:Hyla sauirella Location: Breeding Season:
The Green and Squirrel Tree Frog are very similar. The Green Tree Frog has a stripe that goes down its side while the Squirrel Tree Frog doesn’t. The Squirrel Tree Frog is rarer than the Green Tree Frog and is only found on the southern border of the state.
Common Name: Blanchard’s Cricket Frog Scientific Name: Acris blanchardi Location: Northern border Breeding Season: January through April
The Northern Cricket Frog is the only frog in the state. Its skin is relatively more rough than the other tree frogs in the state. It also has no distinct markings.
Common Name: Cajun Chorus Frog Scientific Name: Pseudacris fouquettei Location: Throughout state Breeding Season: January through April
The Upland and Cajun Chorus Frogs look very much alike. Best way to tell them apart is through genetic tests, call, or by location. The Upland Chorus Frog appears only in the northeastern corner in the state while the Cajun appears everywhere.
Common Name: Boreal Chorus Frog Scientific Name: Pseudacris maculata Location: Northern edge of the state Breeding Season:
The Boreal Chorus Frog is rare and only found along the northern border of the state. It has three lines that run done its back that are rarely broken.
Common Name: Streckler’s Chorus Frog Scientific Name: Pseudacris streckeri Location: Western part of the state Breeding Season:
The Illinois and Streckler’s Chorus Frog are basically identical so best way to tell them apart is where they are found. The Streckler’s Chorus Frog can be found in the western half of the state. The Illinois Chorus Frog can be found in the Northeastern corner of the state. Both frogs differ from the other chorus frogs because they don’t have a white line that extends off the lips.
The Fowler’s and Woodhouse’s Toads both have cranial crests that form opposing L shapes. The Fowler’s Toad has largest, dark spots on its back that have 3 or more warts in them.
The Coastal Plains Toad is notable from the other toads in the family because its in a different genus than them, Incilius instead of Anaxyrus. The genus Incilius has a more defined cranial crest than Anaxyrus.
Common Name: Great Plains Narrow Mouthed Toad Scientific Name: Gastrophryne olivacea Location: Western half of the state Breeding Season:
The Western Narrow Mouthed Toad is found on the western edge of the state. It has a light, unmarked belly and has no patterns and a few spots on its back.
Common Name: Plains Spadefoot Toad Scientific Name: Spea bombifrons Location: Center of state Breeding Season:
The Plains Spadefoot Toad has a rounded spade compared to the other two spadefoot toads. They are extremely rare in the state and found only in 4 spots.
The difference between the Plains Leopard Frog and the Northern Leopard Frog deals with its the dorsal ridge. The Plains Leopard Frog’s dorsal ridge indents near its butt.
The Northern Cricket Frog is found everywhere besides the far western part. Their skin is relatively rougher compared to the other tree frogs in the skin.
The American Toad is found along the eastern edge of the state. The cranial crest and the parotoid gland of the toad do not touch or they connect with a spur.
The Plains Spadefoot toad is the only spadefoot toad in the state. Look at the rear foot of the toad and you will find a keratinized spade on it which no other toad or frog in the state has.
