This page lists 19 species: all from Iowa DNR's List of Iowa Amphibians Evaluated by the IWAP.
Iowa DNR gives a total of 16; the 19 here are the frogs and toads official sources name one by one.
All 19 frogs and toads
From A to Z.
Photo: U.S. Fish and Wildlife Service - Midwest Region · Public domain · Wikimedia Commons
No official source we use states whether this animal is venomous. That does not mean it is harmless: do not handle it.
Size
2 to 3.5 inches long (NCWRC: up to 4 inches); females are larger than males.
How to recognize it
Dark spots on the back hold only a few large warts; the similar Fowler's toad has three or more. Agencies give different counts for the American toad (TWRA: one or two; Ohio DNR: one, two or three; Georgia DNR: usually no more than one), so wart count alone does not settle it; check the head crests too (see lookalikes).
A large, kidney- or bean-shaped parotoid gland behind each eye that usually does not touch the bony ridge (cranial crest) above the eye, or touches it only by a short spur.
No official source we use states whether this animal is venomous. That does not mean it is harmless: do not handle it.
Size
Usually 6 to 8 inches long (NCWRC); can reach 8 inches or more and weigh over 2 pounds (CDFW). Missouri gives 3.5 to 6 inches snout to vent, occasionally to 8.75.
How to recognize it
No ridge (dorsolateral fold) down each side of the back
Large round eardrum: about twice the eye in males, about eye-sized in females
Fully webbed hind feet, longest toe extends past the webbing
Cannot be told apart by sight. In the field they are told apart by the breeding call (Cope's trill is faster and harsher); in the lab by chromosomes. Location also helps: SREL says only Cope's occurs in Georgia and South Carolina.
Maine IF&W lists the spring peeper's distinguishing characteristics: Maine's smallest frog (about 0.8 to 1.5 inches), grayish- or orangish-brown above with a distinct dark X on the back, and smooth skin; it notes it is commonly confused with the gray treefrog.
American toad or Fowler's toad?
Photo: U.S. Fish and Wildlife Service - Midwest Region · Public domain · Wikimedia Commons
The difference official sources agree on is at the head: in the American toad the ridge (cranial crest) behind each eye is separate from the parotoid gland or joined to it only by a short spur; in Fowler's toad the two touch. Fowler's toad also has three or more warts in each of the larger dark spots, while the American toad has fewer (TWRA: one or two; Ohio DNR: one, two or three; Georgia DNR: usually no more than one). Fowler's toad has a whitish belly, often with a single dark spot on the chest; the American toad's belly is peppered with dark spots. The two can hybridize, so some toads cannot be told apart.
The difference official sources agree on is at the head: in the American toad the ridge (cranial crest) behind each eye is separate from the parotoid gland or joined to it only by a short spur; in Fowler's toad the two touch. Fowler's toad also has three or more warts in each of the larger dark spots, while the American toad has fewer (TWRA: one or two; Ohio DNR: one, two or three; Georgia DNR: usually no more than one). Fowler's toad has a whitish belly, often with a single dark spot on the chest; the American toad's belly is peppered with dark spots. The two can hybridize, and hybrids have intermediate features.
Bullfrogs lack the dorsolateral ridges that green frogs have.
Photos show typical adults; individuals vary. Never get close to compare.
When frogs and toads are active in Iowa
Records of frogs and toads in Iowa peak in May to August. They show when people record frogs and toads, not how many there are (about month bars).
JanFebMarAprMayJunJulAugSepOctNovDec
424 records of frogs and toads in Iowa by month (GBIF, CC0 and CC BY records).
Frog calling, approximate (Iowa DNR): chorus frogs March/April; spring peeper and plains leopard frog April; American toad late April-early May; gray treefrogs May; bullfrog and green frog around June. Iowa DNR
How to report
Aquatic invasive species: report suspected sightings to the nearest Iowa DNR fisheries station or by email (address on the DNR AIS page, [email protected] as decoded from the page link). Elk sightings: local conservation officer or wildlife field staff. Nuisance wildlife in a home: a DNR-licensed Nuisance Wildlife Control Operator. Iowa DNR
“They are usually one of the first frogs to start calling in the spring (March/April). / They start calling earlier in the spring, usually in April. / They usually start to call towards the end of April to early May. / They usually start calling sometime in May. / They are one of the later frogs to start calling, usually around June.”
Aquatic Invasive Species. Iowa Department of Natural Resources (Iowa DNR). sitemap lastmod 2026-02-23; checked November 3, 2026.Quoted passages (1)
“Learn to identify aquatic invasive species and report any suspected sightings to the nearest DNR fisheries station.”
.jpg){kind=link}
_-_Flickr_-_2ndPeter.jpg){kind=link}
_-_Flickr_-_2ndPeter.jpg){kind=link}
