The Illinois Chorus Frog might not win any beauty contests, but it has something far more memorable: a squeaky, high-pitched call that sounds almost like a thumb running over a comb. Found in just a few small pockets of the Midwest, this shy little frog spends most of its life underground and only makes a brief appearance each spring. If you want to spot one, you’ll need good timing — and probably muddy boots.
Size & Physical Appearance
These frogs are on the small side, usually ranging from just 1 to 1.5 inches long. Their bodies are plump and a bit stubby, with a soft, almost velvety texture. Coloration varies but generally tends to be light tan to grayish-brown, sometimes with irregular dark markings down the back.
One distinctive feature to look for is a thin, usually dark triangle between the eyes. Their bellies are pale and unmarked, and their heads are relatively large compared to their bodies.
Males and females look quite similar, though males tend to be slightly smaller and have a darker throat during breeding season due to their vocal sacs.
Habitat and Range
This species is a bit of a homebody. It’s found only in a few parts of the central United States, primarily in:
- Illinois (hence the name)
- Missouri
- Arkansas
But even within those states, the Illinois Chorus Frog has a pretty limited range. It sticks to sandy soils in flat, open areas like croplands, grasslands, and prairies. In fact, its preference for sandy soils is a big part of its story — it allows them to burrow quickly and escape dry spells.
You’ll usually find them at low elevations in floodplain regions. They’re especially tied to temporary water bodies like farm ditches and vernal pools that show up after rains in late winter and early spring.
Diet
When they’re active, Illinois Chorus Frogs aren’t picky eaters. They feed mostly on small invertebrates like ants, beetles, spiders, and caterpillars. Because they spend so much time underground, they probably eat a fair number of burrowing insects and larvae too.
Their diet can vary a bit based on what’s available in their short surface-dwelling window each year, but they make the most of it.
Lifespan
In the wild, these frogs typically live around 3 to 5 years, though many don’t make it past their first year due to predators and environmental factors. In captivity (which is rare, since they’re tough to care for), they may live a little longer, but not by much.
Identification Tips
The Illinois Chorus Frog can be tough to spot, but if you hear them calling in early spring (usually from February to April), you’re in luck.
Here’s how to tell it apart from close relatives:
- Western Chorus Frog (Pseudacris triseriata): Has distinctive dark stripes down its back and sides, unlike the blotchy or less-patterned Illinois Chorus Frog.
- Upland Chorus Frog (Pseudacris feriarum): Also more heavily striped and found further southeast.
- Southern Leopard Frog: Much larger, with greenish coloring and more obvious spots.
Keep in mind, coloration in chorus frogs varies a lot, so listen carefully — the call is one of your best clues. The Illinois Chorus Frog’s call is loud, metallic, and sounds like a finger running over a fine-toothed comb.
Fun Fact
The Illinois Chorus Frog is a true underground specialist — it uses its strong forelimbs to burrow downward, head first. That’s unusual for frogs, which almost always dig with their hind legs. This adaptation helps it thrive in sandy soils and avoid both predators and harsh weather. It’s like the mole of the amphibian world!
In Summary
The Illinois Chorus Frog is a secretive little survivor that’s perfectly adapted to a very specific niche. It’s not easy to find, but if you’re in the right spot during the right time of year and you listen closely, you might just catch its strange, comb-like call echoing across a wet field. Just be prepared to get a little muddy if you want a closer look.
Protecting the habitats of these frogs matters — not just because they’re rare, but because they’re a quirky and fascinating part of our natural world.