6 Types of Frogs Found in Colorado! (ID Guide)
“What kind of frogs can you find in Colorado?”
I love finding, observing, and hearing frogs!
Even as a kid, I used to patrol the swamps by my house, catching them and then trying to sell them as pets to cars passing by. As you can imagine, no one was interested in buying my frogs, and I ended up letting them go at the end of each day. 🙂
Today, I’m providing a guide to teach you about the different kinds of frogs found in Colorado.
One of the BEST ways to find frogs is to learn the noises they make. So, in addition to pictures, you will find audio samples for each species below!
6 Frog Species in Colorado:
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#1. American Bullfrog
- Lithobates catesbeianus
Identifying Characteristics:
- Adult body lengths range from 3.6 to 6 inches.
- Coloration is typically olive green, with some individuals having gray or brown mottling or spots.
- Fully webbed back feet.
The American Bullfrog is the largest frog in Colorado!
Believe it or not, they can grow to weigh as much as 1.5 pounds (.7 kg). Naturally, bullfrogs are found in the eastern half of the state. Unfortunately, these massive frogs were also introduced to parts of western Colorado. Their giant appetites can be incredibly destructive to these native ecosystems.
American Bullfrog Range Map
Green = native range. Red = introduced range.
Bullfrogs can be found in permanent bodies of water, including swamps, ponds, and lakes. During the breeding season, the male frogs select egg sites in shallow waters, which they defend aggressively. A female will then select a male by entering his territory.
They are named for their deep call, which is thought to sound like a bull bellowing.
Bullfrogs are known to eat just about anything they can fit in their mouth and swallow! The list of prey includes other frogs, fish, turtles, small birds, bats, rodents, insects, crustaceans, and worms. I have personally witnessed one even trying to eat a baby duck!
#2. Northern Leopard Frog
- Lithobates pipiens
Identifying Characteristics:
- Adults range from 2 to 4.5 inches long.
- Smooth skin is green, brown, or yellow-green with large dark spots.
- Lighter-colored raised ridges extend down the length of the back.
You can spot Northern Leopard Frogs in Colorado near slow-moving bodies of water with lots of vegetation. You might see them in or near ponds, lakes, streams, and marshes. I love how bright green most individuals appear!
Northern Leopard Frog Range Map
Due to their fairly large size, these frogs eat various foods, including worms, crickets, flies, and small frogs, snakes, and birds. In one study, a bat was even observed being eaten!
During the spring breeding season, the males will float in shallow pools emitting a low call thought to sound a bit like snoring. The Northern Leopard Frog may also make a high, loud, screaming call if captured or startled.
Northern Leopard Frog populations are declining in many areas, and the cause is not exactly known. It’s thought to be some combination of habitat loss, drought, introduced fish, environmental contaminants, and disease.
#3. Plains Leopard Frog
- Lithobates blairi
Identifying Characteristics:
- Adults are 2 to 3.75 inches long.
- Tan or light brown coloration with dark brown or greenish spots.
- A distinct white line on the upper jaw and lighter ridges running down the sides of the back.
As the name suggests, this frog is found on the plains of Colorado.
Plains Leopard Frog Range Map
The Plains Leopard Frog is almost always seen around permanent bodies of water, including streams, creeks, ponds, and marshy areas. They primarily eat insects, although these opportunists will eat almost any living thing they can fit in their mouth (including other frogs).
During the breeding season, the males produce a uttural, rapid “chuck-chuck-chuck” call.
The Plains Leopard Frog is relatively common but can be hard to see. First, they are nocturnal. Second, they are shy and dive into the water as soon as they are approached!
#4. Boreal Chorus Frog
- Pseudacris maculata
Identifying Characteristics:
- Adults range from 1 to 1.5 inches long.
- Coloration is brown, olive green, or tan with three dark stripes down the back that are sometimes broken into blotches.
- Prominent black stripe on each side from nostril, through the eye, and down the sides to the groin.
- Looks very similar to the Western Chorus Frog. Boreal Chorus Frogs are distinguished by having shorter legs.
While the Boreal Chorus Frog can be common in Colorado, they are rarely seen. They’re small and secretive, inhabiting moist meadows and forests near wetlands.
Boreal Chorus Frog Range Map
Credit: U.S. Geological Survey, Department of the Interior/USGS
These frogs breed in shallow temporary ponds and pools such as flooded fields and roadside ditches. They require waters free of fish; otherwise, most of their eggs and tadpoles would be eaten!
Males produce a loud chorus of calls at breeding sites, which are easy to identify.
The sound has been compared to someone running a finger over the teeth of a comb (“reeeek“). You’re most likely to hear the calls in the late afternoon or evening.
#5. Canyon Treefrog
- Dryophytes arenicolor
Identifying Characteristics:
- Adults range from 1-2 inches in length.
- Typically brown, gray-brown, tan, or gray-green with darker, irregular blotches on the back. They often match the color of their habitat.
- They sometimes appear golden in direct sunlight, and the inside of the hind legs is bright yellow.
Canyon Treefrogs are found in rocky areas in Colorado. They may be called treefrogs, but this species is mainly found perched on boulders and rock faces near permanent water sources.
Canyon Treefrog Range Map
During the hottest part of the day and periods of low rainfall, Canyon Frogs will seek shelter in rock crevices. They sometimes cluster together in these areas to help reduce moisture loss. They also have tougher skin on their back than most frog species to help them cope with their hot, dry climate.
You may hear the male’s low call during the breeding season, which is sometimes thought to sound like a distant sheep or goat. Since they are nocturnal, your best bet is to hear one at night.
Breeding occurs during spring rains, and the females lay large masses of 100 or more eggs which float in the water.
#6. Wood Frog
- Lithobates sylvaticus
Identifying Characteristics:
- Adult body lengths range from 1.5 to 3.25 inches.
- Coloration is various shades of brown, gray, red, or green, with females tending to be more brightly colored.
- Distinct black marking across the eyes, which resembles a mask.
As the name suggests, Wood Frogs are found in northern Colorado in moist woodland habitats, including forested swamps, ravines, and bogs. They travel widely and visit seasonal pools to breed.
Wood Frog Range Map
This incredible little frog has a wide range across North America. They have adapted to cold climates by being able to freeze over the winter. Their breathing and heartbeat stop, and their bodies produce a type of antifreeze that prevents their cells from bursting. In the spring, they thaw and begin feeding again.
Interestingly, Wood Frogs seem to be able to recognize their family. Scientists have found that as tadpoles, siblings will seek each other out and group together!
Wood Frogs are one of the first amphibians to emerge after the snow melts.
Listen for a call that sounds a bit like a clucking chicken near vernal pools and other small bodies of water!
Do you need additional help identifying frogs?
Try this field guide!
Which of these frogs have you seen in Colorado?
Leave a comment below!
