Indiana’s ponds and wetlands come alive each spring with frog calls that help you identify which species has moved in. This Indiana Frog Identification Guide will help you tell apart the 16 species found across the state, from the tiny Spring Peeper to the massive Bullfrog. You don’t need to be a biologist to identify frogs—just pay attention to size, color patterns, and especially their calls.
Frogs are easier to hear than to see. Most species are masters of camouflage and will stop calling the moment you step close. That’s why learning their sounds is the fastest way to identify them. But visual clues also matter, like the presence of dorsolateral ridges (those raised lines running down a frog’s back) or the shape of their toe pads.
Indiana Frog Identification Guide
This guide covers all native frog species in Indiana. We’ll group them by family and then by common name. Each entry includes size, color, call description, and habitat preference. Print this page or bookmark it for your next night hike.
True Frogs (Ranidae)
True frogs have smooth skin, long legs, and webbed feet. They live in or near water year-round. Indiana has six species in this family.
American Bullfrog
Size: 3.5 to 8 inches. The largest frog in Indiana.
Color: Green to brown with a pale belly. No dorsolateral ridges.
Call: Deep, resonant “jug-o-rum” that carries across ponds.
Habitat: Permanent ponds, lakes, and slow rivers.
ID Tip: Look for the huge tympanum (eardrum) behind the eye. In males, it’s larger than the eye itself.
Green Frog
Size: 2.25 to 4 inches.
Color: Green to bronze with small dark spots. Two dorsolateral ridges run down the back.
Call: A single “gunk” or “twang” like a loose banjo string.
Habitat: Ponds, marshes, and stream edges.
ID Tip: The ridges on the back are the easiest way to separate Green Frogs from Bullfrogs.
Northern Leopard Frog
Size: 2 to 4.5 inches.
Color: Green or brown with round dark spots bordered by light rings.
Call: A low, guttural snore that lasts 2-3 seconds, followed by chuckles.
Habitat: Grassy fields near water, not always in the water itself.
ID Tip: The spots are arranged in two or three irregular rows on the back.
Pickerel Frog
Size: 1.75 to 3.5 inches.
Color: Tan to brown with square-shaped spots in two rows.
Call: A low, steady snore that lasts about 1 second.
Habitat: Cool, clear streams and seeps.
ID Tip: The bright yellow or orange color on the inside of the thighs is a dead giveaway. Also, the spots are more rectangular than round.
Plains Leopard Frog
Size: 2 to 4 inches.
Color: Grayish-green with small, irregular dark spots. A distinct light spot on the eardrum.
Call: A short, grating snore followed by clucking sounds.
Habitat: Prairies, wet meadows, and roadside ditches.
ID Tip: Look for the white spot on the tympanum. This species is less common in Indiana, mostly found in the northwestern corner.
River Frog
Size: 3 to 5 inches.
Color: Dark brown to black with small light spots.
Call: A deep, explosive “waaah” that sounds like a cow mooing.
Habitat: Large rivers and floodplain swamps.
ID Tip: Only found in extreme southern Indiana along the Ohio River. Very rare.
Treefrogs (Hylidae)
Treefrogs have enlarged toe pads for climbing. They are small, often colorful, and have loud calls for their size. Indiana has five species.
Eastern Gray Treefrog
Size: 1.25 to 2.5 inches.
Color: Gray, green, or brown—they can change color slowly. Bright yellow or orange patches on the inner thighs.
Call: A musical, flutelike trill that lasts 1-3 seconds.
Habitat: Woodlands, forests, and suburban backyards.
ID Tip: The bright thigh color is only visible when the frog jumps. The toe pads are large and sticky.
Cope’s Gray Treefrog
Size: 1.25 to 2 inches.
Color: Identical to the Eastern Gray Treefrog. You cannot tell them apart by looks alone.
Call: A faster, harsher trill that is more nasal.
Habitat: Same as Eastern Gray Treefrog.
ID Tip: Call is the only reliable way to separate these two. Cope’s trill is shorter and less musical. In Indiana, both species occur, sometimes in the same tree.
Spring Peeper
Size: 0.75 to 1.25 inches. One of Indiana’s smallest frogs.
Color: Tan to brown with a dark X-shaped mark on the back.
Call: A high-pitched “peep” repeated every second. From a distance, it sounds like sleigh bells.
Habitat: Woodland ponds and temporary pools.
ID Tip: The X on the back is unique. They call early in spring, sometimes when ice is still on the pond.
Western Chorus Frog
Size: 0.75 to 1.5 inches.
Color: Gray to brown with three dark stripes down the back. A dark stripe through the eye.
Call: A rising “creeeeek” like running a finger over a comb.
Habitat: Wet fields, marshes, and temporary pools.
ID Tip: The three stripes are the key feature. They call early in spring, often before Spring Peepers.
Boreal Chorus Frog
Size: 0.75 to 1.5 inches.
Color: Similar to Western Chorus Frog but with a more broken stripe pattern.
Call: A slower, lower-pitched version of the Western Chorus Frog’s call.
Habitat: Northern Indiana, in bogs and cold marshes.
ID Tip: Range is the best clue. Boreal Chorus Frogs are only found in the northernmost counties.
True Frogs Vs. Treefrogs: A Quick Comparison
- True frogs have smooth, moist skin. Treefrogs have slightly rougher skin.
- True frogs have small toe pads. Treefrogs have large, sticky toe pads.
- True frogs spend most of their time in water. Treefrogs climb vegetation.
- True frogs are generally larger. Treefrogs are small to tiny.
Spadefoot Toads (Scaphiopodidae)
Spadefoots are not true toads. They have smooth skin, vertical pupils, and a hard “spade” on their hind feet for digging. Indiana has one species.
Eastern Spadefoot
Size: 1.75 to 2.5 inches.
Color: Gray to brown with two light stripes down the back. The stripes form an hourglass shape.
Call: A short, explosive “waaak” like a crow but softer.
Habitat: Sandy or loose soil areas, often far from water. They burrow underground.
ID Tip: The vertical pupil is unique among Indiana frogs. Also, they have no parotoid glands (the bumps behind true toads’ eyes).
True Toads (Bufonidae)
True toads have warty, dry skin and large parotoid glands behind their eyes. They are terrestrial and only go to water to breed. Indiana has two species.
American Toad
Size: 2 to 4.5 inches.
Color: Brown to olive with dark spots. Each spot contains one or two warts.
Call: A long, musical trill that lasts 10-30 seconds.
Habitat: Gardens, forests, fields—anywhere with cover.
ID Tip: The parotoid glands are kidney-shaped and separate from the cranial crests (the ridges on top of the head).
Fowler’s Toad
Size: 2 to 3.5 inches.
Color: Gray to brown with dark spots. Each spot contains three or more warts.
Call: A short, nasal “waaah” lasting 1-4 seconds.
Habitat: Sandy areas, riverbanks, and open woodlands.
ID Tip: The parotoid glands touch the cranial crests. Also, the belly is usually plain white, while American Toads have spotted bellies.
Narrow-mouthed Toads (Microhylidae)
These are not true toads. They have a pointed snout, a fold of skin across the back of the head, and a very small mouth. Indiana has one species.
Eastern Narrow-mouthed Toad
Size: 1 to 1.5 inches.
Color: Gray to brown with a light belly. No obvious markings.
Call: A high-pitched, bleating “baa” like a tiny sheep.
Habitat: Moist areas under logs or debris, often in floodplains.
ID Tip: The pointed snout and small mouth are distinctive. They look more like a tiny turtle than a frog.
How To Identify Frogs By Call
Call identification is the most reliable method. Here’s a step-by-step process:
- Listen at the right time. Most frogs call at night during their breeding season. Spring is peak time, but some species call into summer.
- Focus on one call at a time. A pond can be noisy. Pick one sound and ignore others.
- Describe the sound. Is it a trill, a peep, a snore, or a croak? How long does it last?
- Compare to recordings. Use apps like iNaturalist or FrogID to match what you hear.
- Note the habitat. A frog calling from a tree is likely a treefrog. One calling from the water’s edge is likely a true frog.
Call Timing Chart
- March-April: Spring Peeper, Western Chorus Frog, Boreal Chorus Frog, Wood Frog (rare in Indiana)
- April-May: American Toad, Fowler’s Toad, Eastern Spadefoot, Pickerel Frog
- May-June: Green Frog, Northern Leopard Frog, Plains Leopard Frog, Gray Treefrogs
- June-July: American Bullfrog, River Frog, Eastern Narrow-mouthed Toad
Visual Identification Tips
When you do spot a frog, look for these features in order:
- Dorsolateral ridges. Present on Green Frogs, Leopard Frogs, and Pickerel Frogs. Absent on Bullfrogs.
- Toe pads. Large pads mean treefrog. Small pads mean true frog or toad.
- Parotoid glands. Present only on true toads (American and Fowler’s).
- Eye pupil shape. Vertical pupils mean Eastern Spadefoot. Horizontal or round means everything else.
- Thigh color. Yellow or orange thighs mean Pickerel Frog or Gray Treefrog.
Common Confusion Pairs
- Bullfrog vs. Green Frog: Bullfrogs lack dorsolateral ridges. Green Frogs have them.
- American Toad vs. Fowler’s Toad: Check if parotoid glands touch the cranial crests. American: separate. Fowler’s: touching.
- Northern Leopard Frog vs. Pickerel Frog: Pickerel Frogs have square spots and yellow thighs. Leopard Frogs have round spots and white thighs.
- Eastern Gray Treefrog vs. Cope’s Gray Treefrog: Call is the only way. Cope’s is faster and harsher.
Where To Find Frogs In Indiana
Frogs are everywhere, but some spots are better than others. Here are top locations:
- State parks: Brown County, Turkey Run, and Shades State Park have good frog diversity.
- Nature preserves: The Nature Conservancy’s Kankakee Sands and Goose Pond Fish and Wildlife Area are hotspots.
- Your backyard: A small pond or even a rain barrel can attract frogs.
- Roadside ditches: Temporary pools after rain are breeding sites for many species.
Best Time Of Year
Late March through June is prime frog season. Warm, rainy nights are best. Bring a flashlight with a red filter—frogs can’t see red light as well, so they keep calling.
Conservation Status
Most Indiana frog species are common, but some need attention. The River Frog is state-endangered. The Boreal Chorus Frog is state-threatened. Habitat loss and road mortality are the biggest threats. You can help by leaving leaf litter in your yard and avoiding pesticide use near water.
Frequently Asked Questions
What is the most common frog in Indiana?
The Green Frog is probably the most widespread. You’ll find them in almost any permanent water body across the state.
How can I tell a frog from a toad in Indiana?
Toads have dry, warty skin and large bumps behind their eyes (parotoid glands). Frogs have smooth, moist skin and no parotoid glands. Toads also walk rather than jump.
Are there poisonous frogs in Indiana?
No frog in Indiana is dangerously poisonous. However, Pickerel Frogs and American Toads secrete skin toxins that can irritate your eyes or mouth. Wash your hands after handling any frog.
What frog sounds like a cow in Indiana?
The River Frog makes a deep “waaah” that sounds like a cow mooing. The American Bullfrog’s “jug-o-rum” is also deep but not cow-like.
Why do frogs stop calling when I approach?
Frogs are sensitive to vibration and movement. They stop calling to avoid predators. Stay still for a few minutes, and they’ll usually start again.
Final Tips For Your Next Frog Hunt
- Bring a notebook and record calls on your phone.
- Use a headlamp so your hands are free.
- Wear rubber boots—you’ll be wading.
- Don’t touch your eyes after handling frogs.
- Respect the animals. Observe, don’t disturb.
With this Indiana Frog Identification Guide, you’re ready to explore the state’s amphibian diversity. Start in your own backyard