Twelve species of frogs make their home in Wisconsin. Frogs need water in which to lay their eggs. As adults, they may live on land, in the water, or even in trees!
This blog gives you lots of information about Wisconsin frogs as well as detailed information about each of the 12 species.
What Do Wisconsin Frogs Do In The Winter?
Wisconsin gets cold in winter and the ground freezes. While we love our outdoor winter sports the frogs are not so crazy about hockey and ice skating.
Frogs seek out places to “hide” in the winter. They will often dig down in the mud, and inhabit crayfish tunnels or small mammal burrows.
Frogs brumate during the winter. Brumation is similar to hibernation. In brumation, their metabolic rate slows way down. They stop eating and urinating.
Only mammals hibernate because in hibernation the animal controls their body temperature. Often lowering it to conserve energy. Amphibians and reptiles can’t regulate their own body temperature.
Some frogs such as wood frogs can actually survive a percentage of their body freezing and then thawing in spring. This is because they have a special “antifreeze in their bodies.
Does Wisconsin Have Endangered Frogs?
Yes, Wisconsin has one endangered frog. The Blanchard’s Cricket Frog is listed as endangered in Wisconsin.
Additionally, we have two species of “special concern” in our state. The Mink Frog and the Pickerel Frog.
Special concern is species that are declining in number. Scientists are taking action to monitor this species to decide what steps to take.
Wisconsin frogs are struggling with habitat loss and water pollution.
Who Eats Frogs?
Frog populations are at risk from natural predation as well. Both adults and tadpoles are delicious and easy prey for many animals. Sandhill Cranes and other shore birds eat large amounts of juvenile tadpoles.
Raccoons love to eat adult frogs and can even eat toads. They do this by carefully eating the toad from the belly and not swallowing the skin on their back. This way they don’t ingest toxins.
Check out this great interview I did with Daniella of toadsnfrogs.com - your questions answered!
Finding Frogs in The Wild
Frogs are an enjoyable species to look for in the wild. Sometimes you don’t have to look far! The picture below shows bullfrogs hanging out in the summer sun.
Often frogs are quiet during the day and require an evening stroll. Go outside on a warm spring evening and listen.
Try to avoid handling frogs. When you pick them up it can frighten them as well as injure their skin. In addition, frogs often have the bacteria salmonella on their skin.
If you want to identify frogs by their calls check out the Environmental Education for Kids website.
The average time frame of when you may hear frogs calling in Central Wisconsin. You may need to adjust for your area. Photo credit Wisconsin Wetlands.
American Toad
Photo by WDNR staff
American Toad (Anaxyrus americanus)
Yes! All toads are frogs, but not all frogs are toads. Just like the infamous thumbs and fingers analogy.
American toads are easy to spot and often live in backyards. Give them some space and don’t scare them by picking them up.
Toads have rough dry skin allowing them to live predominantly on land. Just behind the eyes, they have two large bumps called the parotoid glands.
They live throughout the state of Wisconsin in both rural and urban areas. Toads are toxic to humans and pets. In a pet, the reaction can be quite serious. Call your vet for advice if they have a toad in their mouth or are seen licking one.
The American toad lays its eggs in long strands while most frogs have jelly-like clumps of eggs. Toad tadpoles are also unique in that they will school together after hatching.
Toads produce a musical trill lasting up to 30 seconds. (1)
A Blanchard's cricket frog in Tyson Research Center Missouri. Photo by Freddy
Blanchard's Cricket Frog (Acris blanchardi)
A small tree frog, Blanchards prefers to live around slow-moving streams or still ponds.
This endangered frog likes to breed in marshes, ponds, and mud flats. Places where the water is relatively calm. Larvae stay in the warm shallow waters eating mostly phytoplankton.
Their skin color varies with their environment and ranges from brown, rust, to green. Cricket frog larvae (tadpoles) have unique black-tipped tails.
WDNR considers them to be an S1 which states they are “Critically imperiled in Wisconsin due to a very restricted range, very few populations or occurrences, very steep declines, severe threats, or other factors”.
Over the past 30 years, the Blanchard’s Cricket frog has gone from living in 31 counties to in 2014 only 7 counties.
However, nationally the population is considered declining but still secure. They are in decline along their western and northern regions but have stable populations in southern states.
They are sometimes confused with Spring Peepers. However, their call (1) is very different.
They are more sensitive to cold than other frog species in the state. A study published in the Journal of Herpetology (2) showed only 5% of this species survived the winter.
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Boreal Chorus Frog. Photo by USFWS.
Boreal Chorus Frog (Pseudacris maculata)
This frog is fairly common and can be seen in marshes, wet prairies, and shrub wetlands. They are a light green to tan color and have three brown stripes from head to butt.
Chorus frogs are often confused with spring peepers but look closely. Chorus frogs have horizontal stripes whereas the spring peeper has crossed stripes.
People often compare the chorus frog's call to the sound made when running your fingernail over a fine tooth comb. They are easy to hear but difficult to spot visually. They often hang around in clumps of grass near the water’s edge.
There has been some discrepancy on whether the chorus frog belongs to the boreal or western species. However, scientists have determined those in WI are the boreal species.
Bullfrog. Photo by Carl D. Howe
Bullfrog (Lithobates catesbeianus)
The bullfrog is a common aquatic species. Adults often stay in the water or on the shoreline. They are large in size and have a deep olive color. Males have yellow chins which become very pretty and bright during the breeding season. There
Their call is described as a "jug-o-rum". It is deep and carries for a long distance (1).
Bullfrogs are long living (for frogs) up to nine years.
Cope's Gray Treefrog (Hyla chrysoscelis)
Yes, several species of frogs live in trees. It is a unique adaptation allowing them to avoid ground-dwelling predators, blend in well with their arboreal environment, and they have unique toes suited for climbing.
They hang out on the fringes of forested areas and like the Oak Savannahs.
How many frogs do you see? Color variation among Gray Tree Frogs allows them to blend in with bark and leaves. Photo by Robert Hay, WDNR.
Gray Treefrog (Hyla versicolor)
A close cousin of the Cope’s Gray Treefrog, the Gray Treefrog has a different call.
The gray tree frog may be gray or a lime green color. They have a white spot below each eye and bright yellow inner thigh markings on their underside.
Many frogs limit calling to the breeding season however the gray treefrog often calls throughout warm weather.
A male Northern Green Frog
Green Frog (Lithobates clamitans)
Green frogs are often confused with Bullfrogs. They have similar coloring including a bright yellow chin. The main difference is that green frog adults are about half the size of bullfrogs. In addition, green frogs have brown ridges going about halfway down their back.
They are a water frog and live in and around permanent marshes and ponds. The tadpoles often spend two years in this stage of life.
They have experienced population decline due to development along shorelines.
Mink Frog. Photo by Robert Hay, WDNR
Mink Frog (Lithobates septentrionalis)
In our state, the Mink Frog has S3 status. That means they are considered Vulnerable due to a fairly restricted range, few populations, or recent and widespread declines.
Mink frogs are currently being monitored in several areas of the state. They are found predominantly in the north of the state.
These frogs are shoreline-dependent. They need to be close to the water and come out of the water to find food.
Adults frogs winter over in the water. Larvae also winter over in the water and metamorphize in spring.
Its easy to see where this adorable frog gets his name! The Northern Leopard Frog. Photo by WDNR
Northern Leopard Frog (Lithobates pipiens)
A yellowish-green or light brown frog with large green or brown spots that show where it received its name.
They are widespread throughout the state however leopard frog populations have been in decline since the 1970s. They are fairly comfortable in urban settings however so you may see them in local parks or conservancies.
Pickerel Frog (Lithobates palustris)
This interesting frog prefers cold, fast-moving streams. Adults will move to warmer and calmer waters in the spring to breed and lay eggs.
As you can see by the picture they look very much like Northern Leopard Frogs.
Pickerel Frogs are one of two toxic frogs native to Wisconsin. You can read more in our blog Which Frogs Are Poisonous in Wisconsin?
You can see the X markings on this spring peepers back. Photo by Jimmy Butler.
Spring Peeper (Pseudacris crucifer)
Who does not love these heralds of spring? They are one of the first frogs to start breeding in spring. Every year on my farm in Kentucky the spring peepers would lay eggs in my stock tanks.
They are light brown/tan frogs with a unique irregular dark "X" marking on their back.
Their call is a “peep” which some people label as shrill!
According to the Wisconsin Frog and Toad Survey (3), this species is showing a decline although the DNR still lists them as common.
Wood Frog (Lithobates sylvaticus)
Wood frogs look like they are wearing white lipstick! This pinkish-tan to brown frog has a white upper lip and a dark mask around its eyes.
This small frog has a small range just inhabiting the state’s southwestern counties.
Their call has been compared to a quacking duck. They have a short two-week breeding season which can make monitoring them difficult.
They breed in ephemeral (fishless) pools of water created by snow melt and spring rains.
Fun Fact: Wood frogs have an antifreeze in their bodies that allows them to live in Canada and Alaska.
Check out a frog freeze and thaw in this video!
Declines In Frog Populations
Frogs are sensitive to pollution, climate change, and other disruptions in their environment. As bioindicator species, they can alert scientists when something is wrong.
For instance, frogs may experience growth deformities in reaction to certain chemicals in the water.
In one study (4) the researchers stated that toad and frog populations were declining at a rate of 3.7% per year.
Judy Helgen wrote this book about a frog crisis in neighboring Minnesota.
Author Ame Vanorio is the founder of Fox Run and loves listening to frog calls.
Check out more Wisconsin Wildlife Articles Below
Resources:
Upper Midwest Environmental Sciences Center. USGS. Frog Calls. https://www.umesc.usgs.gov/terrestrial/amphibians/armi/frog_calls.html
2. Smith, G. R., Todd, A., Rettig, J. E., & Nelson, F. (2003). Microhabitat Selection by Northern Cricket Frogs (Acris crepitans) along a West-Central Missouri Creek: Field and Experimental Observations. Journal of Herpetology, 37(2), 383–385. http://www.jstor.org/stable/1566156
3. Paloski, R.A., T.L.E. Bergeson, A.F. Badje, M. Mossman, and R. Hay (eds). 2014. Wisconsin Frog and Toad Survey Phenology Survey Manual PUB-NH-743. Bureau of Natural Heritage Conservation, Wisconsin Department of Natural Resources, Madison, WI. 21 pp. https://www.wiatri.net/inventory/frogtoadsurvey/Volunteer/PDFs/WFTS_PhenologyManual.pdf
4. Adams MJ, Miller DAW, Muths E, Corn PS, Grant EHC, Bailey LL, et al. (2013) Trends in Amphibian Occupancy in the United States. PLoS ONE 8(5): e64347. https://doi.org/10.1371/journal.pone.0064347
Wisconsin has 11 species of turtles. Of these, the Ornate Box turtle is considered endangered and the Blandings and Wood turtles are considered threatened within the state.
Like all reptiles, turtles are cold-blooded or ectothermic which means they rely on the environment for heat. Turtles in Wisconsin have made some neet adaptations to living in a place that gets quite cold in winter.