Frogs in Winter

Have you ever wondered where frogs and toads spend the winter?

They adapt to the cold in a number of ways including freezing solid and then thawing out in the spring!  Learn all about these amazing amphibians during this Frogs in Winter free presentation by Tom Krohn, Arkansas Regional Coordinator for Frog Watch USA and North Central Arkansas Master Naturalist.

It will be presented at the following locations in January:

Saturday, January 3rd, 10:00 - 11:30 am, Fred Berry Conservation Education Center at Crooked Creek, Yellville, Arkansas.  Call (870) 449-3484 to register or email [email protected]

Saturday, January 17th, 1:00 - 2:00 pm, Hobbs State Park, Rogers, Arkansas.  No pre-registration needed

Frogs in Winter

Frogs in winter can be challenged

Ever wonder where the frogs and toads go in the winter?  They are “ectothermic” or cold-blooded animals that depend on the environment to maintain their body temperature.  So where do they hide to avoid being frozen solid in a place like this?

The answer depends on which species you are talking about.  And before we can address that, we need to describe what’s available in the winter environment.

Three choices for a winter home

There is water.  Water would do frogs absolutely no good if it froze solid, but water has the unusual property that ice floats on the surface.  It is less dense than the water it is floating on.  In fact, water becomes more dense as it cools down to 39.16° F.  Then it become less dense the colder it gets until it freezes at 32°.  That means that the temperature of the water at the bottom of a lake or pond will be 39.16° F because the most dense water will sink to that level.

There is earth.  The earth can become cold and freeze during cold weather, but only on the surface down to the frost line.  You see, the earth is a huge heat sink that is not easily frozen.  Below the frost line, the earth stays at a constant temperature - usually in the high 50° F range.

There is debris.  The forest floor is covered with leaves, rotting logs, rocks and stone.  Although these are not great insulators, they provide some protection from the wind and winter precipitation.

Frogs and toads in Arkansas hibernate in the winter.  Their metabolism is greatly reduced or shuts down completely during hibernation.  They find a place to “sleep” out the winter in a shelter called a “hibernaculum.”  So which frogs and toads select each type of shelter?

Where do individual species go?

Aquatic Species - This includes the American Bullfrog, Green (Bronze) Frog, Pickerel Frog, and Southern Leopard Frog.  These four will dive down to the bottom of the pond, lake, or stream and settle in to the mud and silt for the winter.  The water and ice above them are great insulators against the winter.  They stop breathing with their lungs, and blood is increased to the permeable skin where oxygen is obtained directly from the cold water (“cutaneous respiration”).  Their legs are “spread eagle” to keep them in place.  Their second eyelids (nictitating membranes) are pulled up over their eyes which sink deep into their cranial cavities for protection.  They don’t get under the mud because there is not enough dissolved oxygen in it and they would suffocate.  Their hearts continue to pump a small amount of blood, but they don’t eat and spend the winter in a state of torpor.  By the way, Bullfrog and Green frog tadpoles will also over-winter at the bottom and fed on plant material and detritus (waste material).

Toads - This includes the Dwarf American, Fowler’s, Western and Eastern Narrow-mouthed toads, and the three Spadefoot species.  Toads will take advantage of the warm earth below the frost line by digging a burrow (or borrowing one from another animal).  Their metabolism cuts way back, but they continue to breathe and pump blood.  The Crawfish Frog also stays in a burrow all winter.  Unlike the aquatic frogs, these toads, spadefoots, and Crawfish Frog do not assume a “spread eagle” position, but keep their limbs close to their bodies.


Treefrogs - This includes the Bird-voiced, Cope’s, Gray, Green, Spring Peeper and Squirrel treefrogs, the Boreal, Cajun, Illinois, and Strecker’s chorus frogs, Blanchard’s Cricket Frog, and the Wood Frog (which is not a tree frog).  These frogs find hibernacula on the forest floor.  They pull their limbs in, protect their eyes, and shut down under leaf litter, in rotting logs, in a shallow burrow or in cracks and crevices of rocks.  Their bodies produce a kind of glucose antifreeze that keeps their vital organs from freezing, but in many cases their bodies appear to freeze solid - like frogsicles!  Wood Frogs in particular can exist in this mostly frozen state north of the Arctic Circle!  In the spring, these frogs thaw from the inside out.  Foxes like to scratch through the leaf litter in search of a frozen frog treat.

Don’t forget to obtain your 2015 Arkansas Frogs and Toads Wall Calendar here

Frog Calls on SoundCloud

Now you can listen to frog and toad calls from around the country on SoundCloud

Click here to go to


And don’t forget to get your 2015 Arkansas Frogs and Toads Wall Calendar for $10 plus tax and shipping.


Click here for more calendar information


2015 Arkansas Frogs and Toads Calendar now available

This 11″x17″ 2015 Arkansas Frogs and Toads Calendar contains many unique features:

  1. Arkansas frog and toad images taken by Arkansans
  2. Size, range, call, and season for each of the twelve species
  3. An interesting frog or toad fact for each month
  4. Information about Frog Watch USA
  5. An annual chart of frog and toad calling times

This full-color calendar is just $10 plus tax and shipping.  All major credit and debit cards accepted. 

Click on the button to get yours today.
(They make great presents!)

Your purchase of the 2015 Arkansas Frogs and Toads Calendar supports presentations and workshops held around Arkansas.  Thank you . . .

Chytrid Fungus has met its match?

Chytrid fungus targetThe Chytrid fungus (kit-rid) or BD has had a devastating effect on world amphibians since its discovery in the Monteverde cloud forest of Costa Rica in 1987.  But a recent study by a group of European scientists may have found a natural predator of the Chytrid fungus that could save amphibians.  Read this article in Scientific American magazine.

Chytrid Fungus article


Save the Frogs Day - April 2014

L-R Kaitlyn Zamzow, Chelsea Korfel, MaryAnne Stansbury, Jeremy Chamberlain, Peggy & Tom Krohn

Save the Frogs Day - Saturday, April 26th

Peg and I spent an enjoyable afternoon at Pinnacle Mountain State Park south of Little Rock on Saturday. Jeremy Chamberlain and Chelsea Korfel brought several frogs and toads including bullfrogs, a chorus frog, green treefrogs, a dwarf American toad, a southern leopard frog, and an eastern narrow-mouthed toad.

Maryanne Stansbury, the park interpreter, was a great host for the event which drew many families.  The kids were shown how to fold a business card into a frog and then race them.

Save the Frogs Day brings public attention to the importance of amphibians, why they are in trouble, and what can be done to help them.  They can be indicators that the environment is in trouble.

Check out the website at

Garden Frogs

Why Garden Frogs and Toads are Beneficial

1) First and foremost: Frogs and toads eat a LOT of insects.  One individual can eat as many as 10,000 insects in a season.  They do their eating at night so they are not bothered by your gardening chores.  Get rid of your ants, mosquitoes and their larvae, sow bugs, flies, earwigs, slugs, cucumber beetles, caterpillars, grasshoppers, cutworms, and pill bugs.  Turn them into fertilizer through the stomachs of garden frogs and toads.

2) Garden frogs and toads are interesting, benign, and fun creatures.  Children and adults love them.  However, they do have some nasty chemical compounds on their skin, so if you handle them, please wash your hands afterward, and keep your hands away from your face or mouth until you do.

3) Their songs help to thaw out our frozen bones after a hard winter.  Can you imagine camping out in the Spring and not hearing lots of frogs and toads calling for their mates?  That would truly be an alarming “silent spring.”

4) Garden frogs and toads are environmental indicators.  They spend part of their life cycles in water and part on land.  They absorb moisture and oxygen through their permeable skins.  If there is something amiss with the environment, you will notice the consequences sooner with frogs and toads than with your own symptoms.  So if you have lots of frogs and toads around, your water and air are pretty good.

How to Attract Garden Frogs and Toads

1) Garden frogs and toads need three things: shelter, water, and something to eat (insects).

2) They need hiding places: shrubs, logs, piles of rocks, leaf litter, toad houses, a pond.

About toad houses: You can buy great looking, decorative toad houses, but you might not want to put them in your garden for toads.  Try turning a terracotta flower pot upside down with a door broken out of the side.  Or dig a trench and lay a log on top of it with an entrance at each end.  Be sure to place it under a shrub or other shade to keep it cool in the Summer.  Make sure your toad house is open on the bottom and the entry is big enough (4 inches will do).

3) They need hibernating places: leaf litter, ponds, burrows.  Some frogs hibernate at the bottom of a pond and shut down their systems until Spring.

About leaf litter: Don’t be too quick to rake up all your leaves in the Fall.  Many animals, including frogs and toads, use piles of leaves for protection in the Winter.  When they stir in the Spring there will be lots of bugs to eat in the leaf litter.

4) They need water: Frogs need to be near ponds year round.  Toads need ponds during the mating season.  Here are some hints about building a frog/toad pond:

- Make it deep enough so it won’t freeze solid in the Winter (18 inches or more).

- Frogs and toads like still water, so use a minimum fountain or no fountain.

- The tadpoles will keep your pond clean of algae.

- Frogs and toads will keep it clean of mosquitoes and larvae.

How to keep them Healthy

1) Avoid using pesticides, herbicides, and fungicides.  Use natural plantings that are hardy without chemical help.

2) Keep grass around the pond cut short.  Frogs and toads will hide in long grass so you cannot see them, and then will not survive a mower blade.

3) Don’t put fish in your pond.  Fish will eat tadpoles.

4) Provide places to bask and hide.  How about laying a log part in, part out of the pond.  A pile of rocks is a great place to sun bath and hide if necessary.

5) If you use mesh to cover some of your garden crops:  Use a mesh with 1 1/2″ square holes or greater to keep the frogs and toads from getting entangled.

6) Domestic pets:  Do your best to keep your dog and cat separate from your garden frogs and toads.

Timing Considerations

Copyright Anita Hayden

 Mrs. Frog says, “If you build it, they will come.”  Give the garden frogs and toads in your neighborhood time to populate your little piece of paradise naturally.

Don’t try to capture frogs and toads elsewhere and bring them to your place - they will probably either try to migrate back home or possibly die.

And DON’T buy frogs or toads from a pet store and introduce them to your garden.  They are not native creatures.  They will become an invasive species and disrupt the natural balance of your local ecosystem.

It may take a couple of seasons for your garden frog and toad population to balance out, but you will be glad for the effort you put in to attract them.

Frog Call Timing

Frog Calling Phenology (timing)

When do the frogs and toads start to call?  This frog call timing chart will help you practice before you go out to the pond to monitor.

Late Winter/Early Spring: Wood Frogs; Spring Peepers; Southern Leopard Frogs; Chorus Frogs; Pickerel Frog; Crawfish Frog

Spring: American Bullfrog; Dwarf American Toads; Blanchard’s Cricket Frog

Late Spring/Summer: Fowler’s Toad; Green Frog; All the Treefrogs

Anytime after a heavy rain: Narrow-mouthed Toads; Spadefoots

FrogWatch Field Scope Tutorials now available

Watch UTube Tutorials for FrogWatch Field Scope here:

Frog Watch Field Scope Data Entry Tutorial

Frog Watch Field Scope Mapping Tutorial

Frog Watch Field Scope Graphing Tutorial

Frog Watch Field Scope Calling Calendar Tutorial

Frog Watch Field Scope Playlist (4 videos above) 

Learn how to enter your own observation data, map and graph the sites and observations from around the country. You can check out what frogs and toads have been heard in your area and when they started and stopped calling.  A unique feature allows you to view map and graphic data simultaneously on a split screen.

For more in depth knowledge about Frog Watch Field Scope, attend a Frog Watch Workshop scheduled around Arkansas.  Click here for the training schedule.