Wood frogs are generalist predators and will eat almost any prey they can catch, overpower, and fit into their mouths. In the wild, they eat snails, slugs, earthworms, ants, spiders, a wide variety of insects, and other invertebrates. In captivity, they can be fed crickets, dubia roaches, nightcrawlers, mealworms, and other invertebrates.  

Wood frogs develop in two main life stages. They start their lives as tiny tadpoles that live entirely in the water. At this stage, they eat algae, plant tissue, and detritus in their aquatic environments.

After about 65 – 130 days, these tadpoles will through a process known as metamorphosis and develop into the adult form wood frogs that most people are more familiar with.

At this point, they become obligate carnivores and will eat a wide variety of prey they can catch

What Wood Frog Tadpoles Eat in the Wild

Wood frogs start their lives as tiny embryos inside eggs. Their first food source for the developing embryos is the yolk of their eggs.

The yolk provides enough nutrition to sustain the developing tadpoles until they are ready to hatch into the water. This can take anywhere from 9 to 30 days.

After hatching, the tadpoles will have poorly developed gills, mouths, and tails – so they can not properly swim or eat yet.

For this reason, they will spend the first few days feeding on the remaining yolk of the eggs. This will provide them with enough energy to grow and develop further.

After about a few days, the tadpoles would have developed enough to start free swimming and feeding on food sources available in the water.

At this early stage, wood frog tadpoles are mostly herbivorous, and will eat:

• Algae
• Soft roots and leaves of aquatic plants (eg. duckweed mosses)
• Phytoplankton
• Detritus (mostly composed of degraded plant materials)

Due to a mostly herbivorous diet, the tadpoles have very long tightly coiled intestines, that make up more than half of their body mass.

Plants contain cellulose, a compound that is very hard to digest. Because of this, plant matter needs to spend more time in the digestive system. This long intestinal tract gives tadpoles more time to break down the plant matter and absorb as many nutrients as possible.

Wood Frog Tadpoles Become Omnivores

A few weeks into their development, the tadpoles start to grow legs, starting with the back legs. Their digestive tract will also gradually shorten.

Wood frog tadpoles at this stage become omnivores and will eat animal protein in addition to plant matter.

They will also eat:

• Aquatic insect larvae (glass worms, mosquito larvae, etc.)
• Water striders
• Zooplankton
• Small insects that fall into the water
• Worms
• Carcasses in the water

Wood frog tadpoles will also eat eggs and larvae of some salamanders and frogs, including those of wood frogs.

Whatever they eat, they will eat constantly. They have high energy demands because they are growing very rapidly. Growing big as fast as possible is necessary for survival, as it enables them to escape their ponds before they dry up.

What Juvenile Wood Frogs Eat in the Wild

After about 65 – 130 days, the tadpoles will go through a process known as metamorphosis, in which they will transform into juvenile frogs.

During metamorphosis, the thyroid gland secretes a growth hormone called thyroxine.

This hormone triggers the tadpoles to:

• Lose the gills, and develop lungs for breathing air
• Absorb the tail into the body
• Grow strong legs for moving on land
• Remodel other organs to form an adult frog

In addition, the digestive tract shortens dramatically, and the inner lining of the remaining intestine thickens, creating many folds in the process. These folds create a very large surface for the absorption of nutrients during digestion.

Once metamorphosis fully is complete, tiny wood frogs will leave the water and live on land.

At this point, Wood frogs become obligate carnivores, which means they stop eating plant matter and will only eat animal-based foods.

Their diet will shift away from aquatic prey and toward mainly terrestrial prey. However, since they are not fully grown yet, they can only eat small live prey.

Wild Juvenile Wood frogs will eat:

• Ants
• Mites
• Small worms
• Small snails, slugs
• Spiders
• Beetles
• Termites 
• Springtails 
• Fruit flies, and other small insects

As they grow in size, they will be able to eat larger prey.

What Adult Wood Frogs Eat in the Wild

Adult Wood frogs are fully grown, meaning they have bigger mouths and stronger jaws. They basically eat a larger version of the diet they did as juveniles, but their larger size also allows them to eat things they did not eat as juveniles.

Like the juveniles, adult Wood frogs generally prefer to eat live prey and will almost not eat dead bugs or other dead prey items.

Here’s a list of things that make up an adult Wood frog’s diet in the wild:

• Worms, slugs, snails 
• Beetles, stinkbugs, wasps, bees, grasshoppers, cockroaches
• Spiders, centipedes, millipedes
• Mosquitos, termites, ants, mites, springtails 
• Mosquitoes, fruit flies, crane flies, crickets
• Moths (and their larvae), butterflies (and their larvae), and a wide variety of other insects

Adult Wood frogs are generalist carnivores and will eat just about anything they can fit in their mouths. During spring and summer nights, they often catch and eat insects as they fall to the ground under outdoor lights.

Most frogs use their long tongues to catch prey. In the process, an extensive amount of tongue surface is applied in the feeding strikes, resulting in the prey being engulfed by the fleshy tongue.

However, wood frogs make contact with the prey with just the tip of the tongue, much like toads.

Once the prey is in the mouth, the frog will swallow it whole (although frogs have teeth, they do not use them to chew, but rather to maintain a grip on their prey as they swallow it whole).

A frog can shoot out its tongue, capture prey, and pull it back into its mouth within 07 seconds; which is five times faster than the human eye can blink. This speed makes it effective at catching even fast-flying insects such as flies.

What Adult Wood Frogs Eat In Captivity

Captive Wood frogs can eat all the food they would eat in the wild. The only reason they have a different diet is that most hobbyists cannot easily obtain the wide variety of prey these frogs eat in the wild.

So they are limited to only prey items they can purchase or culture on their own.

However, even in captivity, Wood frogs have to be fed live prey. These live prey items can be purchased in a pet store, online, or even from another hobbyist.

Alternatively, you could culture feeder insects at home if you are up for the challenge.

Here’s a list of things you can feed a Wood frog in captivity:

• Crickets, dubia roaches, orange head roaches
• Wingless fruit flies, nightcrawlers
• Mealworms, waxworms, Super worms,
• Phoenix Worms, black soldier fly larvae
• Silkworms, hornworms

Wood frogs are not picky eaters, and will readily accept most soft-bodied invertebrates. Crickets and Dubia roaches can make up a majority of their diet. However, the key to a healthy frog is a varied and nutritious diet, so remember to switch up the food items offered every few feedings.

Be careful to feed the proper size prey for your frog’s size. A good rule of thumb is that a cricket should never be larger than the distance between the frog’s eyes, or the distance from its eyes to its nose.

Also, IT IS NOT RECOMMENDED to feed red wigglers (Eisenia fetida) to captive amphibians. This is because they exude a noxious fluid that contains a toxin known as Lysenin – which is poisonous to many animals.

When feeding insects with a hard exoskeleton to your pet (such as mealworms or super worms), try to make sure the insects have recently molted, as an insect with a large, hard exoskeleton is difficult to digest and may cause impaction.

As for fruit flies, I recommend Hydei fruit flies as they are considerably bigger than the Melanogaster fruit flies and make a richer meal for your frog.

Can You Feed a Captive Wood Frog Wild Bugs?

You could feed your Wood frog wild-caught bugs. Just be 100% sure they are from a clean area that’s free of pesticides or other chemicals. Avoid feeding bugs that can sting or bite, such as large spiders, hornets, bees, etc.

However, it is generally not a good idea to feed captive toads wild bugs or other wild prey. This is because wild insects may carry diseases and parasites that your toad is vulnerable to.

Also, wild bugs in a seemingly clean area could be carrying pesticides they picked up from another area.

Gut-Loading & Nutrient Supplements

Captive-bred feeder insects are often raised on a cost-conscious diet that is meant to help them grow quickly. This means they are not as nutritious as wild insects that eat a wide variety of vitamin and mineral-rich food.

If your frog is given a low-nutrient diet, it could develop health problems such as metabolic bone disease – which is a fairly common issue in captive amphibians.

For this reason, it is important to increase the nutritional value of the food you give to your frog.

This is mainly done in two ways: dusting, and gut loading.

Gut Loading

Gut loading is the process by which feeder insects are fed nutrient-dense foods at least 48 hours before they are offered to the frog. The intention is to pass those nutrients on to the toad when the insects are eaten. 

The process is simple

• Give your feeder insects nutrient-dense foods, such as fresh vegetables with lots of vitamin C.
• After eating this food, the feeder insects will be much more nutritious and pass the nutrients on to the frog when they are eaten.

Dusting

Besides gut loading, another way to ensure your frog gets all the vitamins and minerals it needs is by dusting its food with high-quality powder calcium and vitamin supplements.

Most hobbyists use commercially manufactured supplement powder specifically designed for reptiles and amphibians.

The process is simple:

• First, add a small pinch of supplement powder into a small container such as a cup or an empty cereal container. The powder should only be enough to lightly dust the insects.
• Place one feeding’s worth of feeder insects in the container
• Gently shake the container so the supplements lightly coat the insects
• Once finished, you can offer the dusted insects to your frog

It is a good idea to consult a veterinarian for specific directions on supplementing your pet’s food since many variables go into determining the best supplementation regimen for each animal.

Following your veterinarian’s instructions could help you avoid over-supplementing food.

Otherwise, a good starting point is to dust with a good quality calcium supplement fortified with vitamin D3, 2-3 times a week.

How Much & How Often to Feed Your Wood Frog

Generally, adult Wood frogs will have to be fed every two or three days, while young frogs will need to be fed every day or two.

However, this is not set in stone. If an adult does not eat much during feeding sessions, they may have to be fed every other day.

In addition, the enclosure’s temperature will determine the feeding frequency.

If the temperature is low, your Wood frog will have a slower metabolism and be less active, so it won’t need to each much.

At warmer temperatures, your Wood frog will have a much faster metabolism and will need to be fed much more frequently (every other day).

Regarding how much to feed your Wood frog, the general rule is to only offer as much as the frog can eat in a 20-minute feeding session.

Be careful to not overfeed your frog. Use personal judgment to ensure most of the food offered is being consumed.

Avoid leaving uneaten food (such as crickets) in the enclosure for too long as they can bite or irritate the toad. Remove all uneaten food within 6 hours of feeding.

How Long Can a Wood Frog Go Without Food?

Generally, healthy adult Wood frogs can go for as long as two weeks without food if the environmental temperatures are low, and the frogs have a reduced rate of metabolism.

Juvenile Wood frogs can not survive long without food as they are still growing and have higher energy needs.

However, this isn’t to say you should test the endurance of your frog.

In most situations, it’s a good idea to offer food to your Wood frog at least two to three times per week.

What Human Foods Can Wood Frogs Eat?

Adult Wood frogs are obligate carnivores that are instinctively attracted to movement while hunting for food. For this reason, they will not eat the vast majority of human food.

Humans do not typically eat live food and tend to cook most of their food, so human food will not even register as food to most frogs, including Wood frogs. If you try to offer human food to a Wood frog, it will not eat it.

How to Feed a Wood Frog in Captivity

The most straightforward way to feed a frog is to simply dump the food into its enclosure and let the frog have its fill.

However, some amphibian owners find it easier and safer to feed their pets in a separate enclosure, free of bedding and furniture.

This way you can be sure your frog eats all its insects, the prey cannot hide, and the frog will not pick up any bedding when grabbing prey and mistakenly ingest it along with the prey.

Some frogs, especially those that are still getting used to a new place may be shy and reluctant to eat. In this case, you could entice the frog to eat with the use of some feeding tongs.

Use the tongs to gently hold the food item, then rub it near the nose of the frog. Once he sees it, he will grab it and eat it.

Common Feeding Mistakes

There are a few common mistakes many new toad owners make when feeding their pets.

Using Dead Bugs

In the wild, frogs and toads are ambush hunters that are attracted to prey by movement (motion). For this reason, Wood frogs won’t eat dead bugs. If you offer your Wood frog dead bugs, it will most likely ignore the food and starve. You should only offer live bugs and other prey items.

Using the Wrong-Sized Feeder Insects

Frogs do not chew their food but rather swallow it whole. Feeding a tiny frog a disproportionately large insect could lead it to choke.

Never give a frog anything larger than the distance between its eyes. The bigger the toad, the larger the prey it will be able to eat.

Forgetting to Gut Load Insects

As mentioned earlier, captive-bred feeder insects do not contain as many nutrients as wild insects. They are often raised on a cost-conscious diet that is aimed at making them grow quickly and keeping costs low.

Forgetting to gut load or dust insects before feeding them to your Wood frog means the frog will not get all the nutrients it needs. This nutritional deficiency can lead to serious health problems, and could even be fatal.

Not Using a Varied Diet

Different food items have different nutrients. Not giving a Wood frog a varied diet means it will not get the right variety of nutrients it needs and may end up weak and malnourished.

Switch up the food items offered to the frog every few feedings so it gets a nutrient-rich diet.

Feeding Food With High-Fat Content Too Often

Captive amphibians are not very active animals, so they do not burn off calories. This means giving a captive Wood frog high-fat food (such as wax worms) too often may lead to obesity.

Obesity can then lead to many health problems. For this reason, it is important to limit food with a high fat content to only an occasional treat.

Overfeeding/ Underfeeding

Overfeeding a frog can lead to obesity, which could lead to several health problems. Alternatively, underfeeding means the toad will be undernourished and have poor health.

Common Questions About Wood Frog Diet

Do Wood frogs eat ants? Wood frogs eat ants they can catch. They are very opportunistic predators with very diverse diets – and ants are not off the menu. A single Wood frog can eat hundreds of ants every day.

Do wood frogs eat grasshoppers? In general, Wood frogs eat grasshoppers. However, some grasshopper species such as the eastern lubber grasshopper secrete a toxic foamy, slimy liquid with a nauseating, which makes them foul-tasting, so most Wood frogs will avoid eating them.

If a Wood frog eats a toxic grasshopper, it may gag and regurgitate the insect. For this reason, most frogs quickly learn to avoid eating toxic grasshoppers.

Do Wood frogs eat grass? Wood Frogs do not eat grass. They are obligate carnivores, which means they only eat animal matter. Adult frogs have short alimentary canals, suited for their strictly carnivorous diets – and can not digest grass, or other plants.

Do Wood frogs eat mosquitoes? Wood frog tadpoles eat mosquito larvae in the ponds they live in. Adult Wood frogs eat mosquitoes, found in their environments. For this reason, Wood frogs (and other frog species) help control the population of these pest insects.

Do Wood frogs eat butterflies? In general, wood frogs eat butterflies they can catch and fit into their mouths. In addition, they also eat butterflies in their larval form (caterpillars).

Sources:

Virginia Herpetological Society. Wood Frog Lithobates sylvaticus. Accessed at: https://www.virginiaherpetologicalsociety.com/amphibians/frogsandtoads/wood-frog/index.php

Kiehl, K. 2015. “Lithobates sylvaticus” (On-line), Animal Diversity Web. Accessed at: https://animaldiversity.org/accounts/Lithobates_sylvaticus/

Cardini, F. (1973). Characteristics and Adaptedness of Feeding Behaviors of North American Anurans, Paper presented at June 1973 meetings of the Animal Behavior Society, Amherst, MA

AmphibiaWeb. University of California, Berkeley, CA, USA. Rana sylvatica (LeConte, 1825) Wood Frog. Accessed at: https://amphibiaweb.org/cgi/amphib_query?where-genus=Rana&where-species=sylvatica&account=lannoo

Ezra Mushala

Hi, my name is Ezra Mushala, i have been interested animals all my life. I am the main author and editor here at snakeinformer.com.

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Many wood frogs lay their eggs communally, so it’s common to find large stretches of wood frog eggs floating in the same pool.

Like other frog eggs, wood frog eggs do not have a hard outer shell to protect the developing embryos. Rather, each egg has a jelly coat.

This jelly coat absorbs UV-B some radiation, and also indirectly protects the eggs by virtue of its sticky texture and its tendency to accumulate a covering of pond debris.

Learning about wood frog eggs is great to add to your knowledge and feed your curiosity. Read on to find out everything you need to know about wood frog eggs including some really interesting facts, as well as how to easily identify them.

When Do Wood Frogs Lay Their Eggs?

Wood frogs lay their eggs in the springtime from March through May, depending on the latitude.

Wood frogs are often one of the first frogs to begin the breeding season; and may even begin breeding in early March, before the snow is completely gone, and when their breeding ponds are still partly frozen.

Wood frogs migrate to their breeding sites, on the first few rainy nights in early spring when the night temperature is above 40 degrees. This mass migration is often referred to as “the big night”.

In some towns, people close roads and gather to watch thousands of frogs and salamanders on their breeding migration.

During this migration, Wood frogs can travel significant distances, sometimes up to half a mile, to reach their breeding sites.

Wood frogs are explosive breeders, and breeding will typically occur over a one or two-week period.

Where Do Wood Frogs Lay Their Eggs?

Wood frogs lay their eggs in shallow, standing, freshwater bodies that are free of predatory fish. This could be in; seasonal pools, river backwaters, bogs, marshes, temporary rain puddles, and even in roadside ditches filled with rainwater.

However, Wood frogs very strongly prefer to breed in “vernal pools“, sometimes called  “ephemeral pools.”

Vernal pools are temporal pools of water that form in the spring. They are formed when depressions on the ground are filled with water from melting snow and falling rain.

They are typically small and shallow, and unlike a pond or lake, they have no permanent source of water. This means they dry up in the summer.

Since they are temporal, they do not have fish or many other aquatic predators that could eat the eggs before they hatch.

This makes them ideal breeding sites for wood frogs and, many amphibians.

How Do Wood Frogs Lay Their Eggs?

Male wood frogs typically arrive at the breeding ponds before the females. Once they arrive, the males will begin to call for females (their call has been described as sounding like a flock of ducks quaking).

When the females arrive, the males will try to grab them from behind in a tight mating embrace called ‘amplexus’.

Once in the amplexus embrace, the pair will swim around as the female chooses a site to lay her eggs.

The female deposits a single egg mass on a twig just below the water surface, and the male releases sperm into the water, to fertilize the egg mass as the female lays it.

As earlier mentioned, wood frogs often lay their egg masses communally, so it’s common to find large rafts of wood frog egg masses, containing many layers of masses on top of one another.

Communally laid rafts are thought to create better conditions for development by raising the temperature of the embryos compared to the surrounding water. Warmer temperatures mean the eggs hatch quicker.

How Many Eggs Do Wood Frogs Lay?

In general, wood frogs can lay anywhere from 1,000 to as many as 3,000 eggs. Like in many other frog species, female body size is positively correlated with clutch size.

For this reason, large female Wood frogs will typically carry and lay more eggs than smaller females.

What Do Wood Frogs Look Like?

When first laid, wood frog egg masses are small and tightly compact, (about the size of a quarter), and are embedded in special secretions from a gland in the frog’s body.

Over a few hours, these secretions combine with water to create a jelly-like coating around each egg, and the egg mass swells up to approximately 5 inches (roughly the size of a softball).

This jelly coat around each egg absorbs some UV-B radiation, and also indirectly protects the eggs by virtue of its sticky texture and its tendency to accumulate a covering of pond debris.

Once the egg masses absorb water and reach their maximum size, wood frog egg masses look like clumps of clear jelly-like globs, with a developing embryo visible inside each egg.

Looking down at an egg mass, the embryos will look black or dark brown and blend in with the surrounding darkness of the bottom of the pool. The undersides of the egg masses are a contrasting white or cream color.

At a distance, wood frog egg masses appear bubble-like, where they break the surface of the water.

Over a short time, wood frog egg masses will deteriorate and flatten to the point where individual masses are no longer identifiable from the rest of the large floating raft. They may even become colonized by symbiotic algae, giving them a greenish coloration.

Green egg masses floating at the water’s surface might easily be mistaken for clumps of algae.

Do Wood Frogs Care For Their Eggs?

Wood frogs do not show parental care for their eggs. After the mating is complete, both the males and females will leave the pond, abandoning the eggs.

This means the eggs are all on their own and are at the mercy of the environmental conditions. They are also easy meals for lots of predators.

How Long Do Wood Frog Eggs Take To Hatch?

Wood frog eggs take about 9 to 30 days to hatch, depending on the environmental conditions. The eggs will typically develop and hatch faster in warmer temperatures and slower in colder temperatures.

Wood frog eggs laid in early when the weather is cooler will usually take longer to hatch than those laid in warmer weather.

What Do Wood Frog Tadpoles Look Like?

When they first hatch, wood frog tadpoles are very dark in color and about .25 inches long. As they grow, the dorsal color becomes brown and the venter develops gold flecking, giving them a more mottled appearance.

Newly hatched wood frog tadpoles remain with the egg mass for a few days, feeding on algae associated with the egg masses.

After a few days, the tadpoles leave their egg masses and begin feeding on phytoplankton and algae near the water’s surface.

Wood frog tadpoles often school in shallow areas of the pool or float near the surface. Doing this allows them to absorb solar heat, in the relatively cool waters of a vernal pool.

The tadpoles grow very rapidly and will undergo metamorphosis in about 2 months. This short larval period allows them to escape their temporal pools before the water dries up.

Do Wood Frogs Care For Their Tadpoles?

Some frog species such as the African bullfrog (Pyxicephalus adspersus) protect and attend to their tadpoles to improve their chances of survival.

However, wood frogs do not attend to their tadpoles or care for them in any way. Once mating and egg-laying is complete, both the males and females will leave the pond, only returning the next breeding season.

The Differences Between Wood Frog Eggs And Salamander Eggs

Wood frogs and salamanders (especially spotted salamanders) usually lay eggs in the same pools. Since these egg masses look very similar to each other, they can be difficult for the untrained eye to tell apart.

Here is how you can tell wood frog eggs from salamander eggs:

1. Appearance

The easiest way to tell wood frog eggs from salamander eggs is to look at the outer layer of the egg mass. Salamander egg masses are surrounded by a jelly coat, but wood frog egg masses are not.

If you took a close look at a wood frog egg mass, you would easily notice the contour of each individual egg on the outer layer of the egg mas. This contour gives wood frog egg masses a bumpy surface, sort of like a cluster of grapes.

On the other hand, if you looked at a spotted salamander egg mass, you wouldn’t see the contour of the eggs on the outer layer, since the entire egg mass is covered in an outer layer of jelly.

The surface of the egg mass would look smoother and more uniform. However, if you looked very closely into the jelly, you would see the outline of each egg within the mass.

When floating on the surface of the water, wood frog eggs will look bubbly and bumpy, while spotted salamander eggs will look like blobs of jelly with eggs visible inside.

Also, salamander egg masses sometimes have a cloudy white coloration, but this is never the case for wood frog eggs.

2. Texture

Another difference is that salamander eggs tend to be firmer and denser than wood frog eggs. If you were to gently poke salamander egg mass, it would meet your finger with resistance, while a wood frog egg mass would feel loose and give in to the slightest pressure.

Also, if you were to pick up a salamander egg mass, it would hold its shape even out of water. However, if you picked up a wood frog egg mass, it would be looser and the eggs would fall apart more easily.

3. Location Within the Pool

Also, wood frogs and many salamanders (such as the spotted salamander) deposit their eggs communally, they do so in different ways.

Wood frogs often lay their eggs in large rafts. It is common to find large communal masses in a single area with eggs from multiple wood frogs.

On the other hand, salamanders such as the spotted salamander lay their eggs in individual clusters widely dispersed within a pool. Even when laid on the same stick, individual masses are very clearly identifiable.

What Animals Prey On Wood Frog Eggs?

Wood frog eggs are preyed on by many animals including newts, turtles, leeches, dragonfly larvae, diving beetles, and other large water bugs.

Once wood frog tadpoles hatch, they are preyed on by various aquatic insects (diving beetle adults & larvae, giant water bugs, etc.) as well as northern water snakes, ribbon snakes, turtles, and various wading birds.

What To Do If You Find Wood Frogs Eggs

If you live near a wooded area, especially near a pond, or another water body there’s a chance of encountering wood eggs in the spring. If this happens, be sure to avoid disturbing the eggs.

Disturbing or removing the eggs from the water could damage them, or even kill the tiny embryos developing inside the eggs.

If you find wood frog eggs out of the water, it is best to leave them alone, especially if they are very near the water.

However, if you find wood frog eggs that were disturbed (by a human or animal) and taken out of the water, you could try to put them back in the water.

If the egg mass is still attached to a stick, very gently put the stick back in the water (just a few inches below the surface).

Still, the eggs are not guaranteed to hatch because the disturbance may have damaged them or killed the embryos developing inside.

Of course, there’s no harm in observing wood frog eggs from a distance.

Featured image credit: mariepatricia (CC BY-NC 4.0)

Sources:

Brady, Steven. (2013). Microgeographic maladaptive performance and deme depression in response to roads and runoff. PeerJ. 1. e163. 10.7717/peerj.163.

Corn, P. S., & Livo, L. J. (1989). Leopard Frog and Wood Frog Reproduction in Colorado and Wyoming. Northwestern Naturalist, 70(1), 1–9. https://doi.org/10.2307/3536918 

Virginia Herpetological Society: Wood Frog Lithobates sylvaticus

AmphibiaWeb. Rana sylvatica: Wood Frog. University of California, Berkeley, CA, USA.

Kiehl, K. 2015. “Lithobates sylvaticus“, Animal Diversity Web.

Canadian Herpetological Society:  Wood Frog Lithobates sylvaticus 

Ezra Mushala

Hi, my name is Ezra Mushala, i have been interested animals all my life. I am the main author and editor here at snakeinformer.com.

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The post Everything You Need To Know About Wood Frog Eggs first appeared on Snake Informer.

Wood frogs are very mildly poisonous. When threatened, they produce a poisonous skin secretion that tastes bad to predators. However, this secretion is very mild and is only known to be effective in deterring shrews. The secretion is not of any real threat to humans, dogs, cats, or other pets. 

The only real danger wood frogs pose to humans (or pets) is that, like other amphibians, they can be carrie rs of salmonella and other harmful bacteria which can be transmitted to humans (or pets) if proper hygiene is not practiced.

As a safety precaution, do not touch or handle wood frogs or any other amphibians unless necessary.

If you do handle a wood frog, remember to thoroughly wash your hands with antibacterial soap and water after. Do not rub your eyes or stick your fingers into your mouth or nose before washing your hands.

Wood Frogs Are Only Very Mildly Poisonous

Wood frogs have a skin secretion that is extremely mild to the point where it has no noticeable effect on most predators apart from giving the frog a slightly foul taste. If you ever ingest this secretion, it may cause some irritation or discomfort but probably nothing more serious.

Since their toxin is only mild, wood frogs are often preyed on by larger frogs, snakes, birds, and many small mammals.

However, this does not mean these frogs are totally defenseless when it comes to fending off these predators. They have other ways to protect themselves.

Wood Frogs Are Not Venomous

If you are like most people, you have probably used the words ‘poisonous’ and ‘venomous’ interchangeably at least once. However, you should know that there are significant differences between the two terms.

Sure both of these terms refer to toxins that can be harmful to us, but the key difference lies in how these toxins are delivered.

• If an animal has to bite or sting you to inject its toxins, it is venomous (think rattlesnakes)
• If an animal secretes its toxin on its skin, and you absorb that toxin when you touch the animal, it is poisonous (think poison dart frogs).

In other words, venom is actively injected, usually through stings, fangs, or barbs. Poison on the other hand is delivered much more passively and has to be absorbed/ingested into your body.

It can be ingested when it comes into contact with your eyes, lips, the mucus lining of the nose, or open cuts on your skin.

Wood frogs have a noxious skin secretion to stop predators from eating them, but cannot actively inject this secretion into a predator. This means they are poisonous, but not venomous.

What Other Ways Do Wood Frogs Defend Themselves?

Since wood frogs only have a mild toxin, they may seem defenseless when it comes to fending off hungry predators.

However, they have a few tricks to keep predators away.

As the first line of defense, wood frogs have a cryptic coloration that helps them camouflage or blend into the leaves and other debris in their environments, escaping the notice of most predators.

However, sometimes camouflage alone is not enough, so wood frogs also have very quick responses. If they see a predator getting too close, they can use their powerful hind legs to quickly leap away and escape. Some wood frogs can leap over 30 times their body length!

When captured by a predator, a wood frog may let out a piercing scream that may startle the attacker enough to release the frog.

Are Wood Frogs Dangerous to Humans?

Wood frogs typically aren’t dangerous to humans. While they do produce a mildly toxic skin secretion when threatened, the secretion isn’t potent enough to be of serious harm to humans. Granted, it may cause some irritation or discomfort, but only if you somehow ingest it.

The toxin is not absorbed through your skin but can be absorbed through breaks or cuts on the skin, and the mucous membranes in your eyes, nose, or mouth.

This can happen when you pick up a wood frog with your bare hands, then rub your eyes, or stick your fingers in your nose or mouth without first washing your hands.

Doing this would enable the toxin to be absorbed by your mucus membranes and likely lead to irritation, but usually nothing more serious.

It’s Not Just Toxins to Be Worried About

Nearly all amphibians (including wood frogs) can carry salmonella bacteria, which can be harmful to humans.

Wood frogs can carry salmonella bacteria in their digestive tract and excrete it in their waste. The bacteria do not cause any illness in the frog – so a wood frog carrying salmonella bacteria can look clean and healthy, but the bacteria can be transmitted to humans.

Humans can be exposed to salmonella by direct or indirect contact with a frog, its waste, or anything the frog came in contact with. (For example, you touch a wood frog or its droppings, then touch stick your fingers into your mouth without first washing your hands).

Exposure to salmonella can cause an infection called Salmonellosis which is characterized by stomach cramps, diarrhea, fever, nausea, and sometimes vomiting. The infection is usually mild and non-life-threatening – but in some cases, the bacteria can get into the bloodstream leading to serious illness.

For this reason, it is advisable to avoid handling wood frogs unless when necessary. Even though the frog only secretes a very mild toxin, it may be carrying bacteria that can make you sick.

Are Wood Frogs Dangerous to Dogs or Cats?

Wood frogs only have a mildly toxic skin secretion that does not affect most predators, so they are typically harmless to dogs, cats, or other pets, even if eaten. However, as mentioned earlier wood frogs can carry salmonella bacteria so a dog or cat that mouths, bites, or eats a wood frog may consume the bacteria and develop an infection.

Also, most frogs can carry tapeworms and other parasites. This means if a dog eats a wood frog, it may also consume parasites and develop a parasitic infection.

For this reason, it’s a good idea to keep your pets away from any frogs, even if they are not very toxic.

Safety Precautions to Take When Handling Wood Frogs

It is usually not a good idea to handle frogs and other amphibians. This is because they have a very delicate absorbent skin, that they use to absorb water, oxygen, and other soluble substances.

Oils and salts, that naturally occur on our hands can pass right through the frog’s skin and end up inside its body. Sunblock, repellents, lotions, perfumes, soap, or any other chemicals on your hands can also pass through a frog’s skin and cause harm.

For this reason, it’s advisable to observe amphibians from a distance, without physically touching them.

If you ever need to handle a wood frog (such as moving it off a road), take the following precautions to protect both you and the animal.

 Before Handling 

• Very thoroughly wash your hands. Make sure that your hands are so clean that no residue of soap or any other substance remains on them.

When Handling

• Keep the frog away from your eyes nose and mouth and, be very careful not to rub your eyes, or touch your nose, or mouth.
• As you handle the frog, do it very gently and with care so you do not injure or stress it in any way. Avoid squeezing the frog too hard, or applying too much pressure on it.

What to Do After Handling

• Very thoroughly wash your hands with anti-bacterial soap under running water.

Even if you were wearing gloves, it is still a good idea to go the extra mile by washing your hands. As earlier mentioned, wood frogs produce a noxious skin secretion and may carry bacteria that can be harmful, so it’s best to protect yourself.

Before washing your hands, do not touch anything (you could spread bacteria) – and remember not to rub your eyes, touch your face, or put anything into your mouth.

Frequently Asked Questions

Are wood frogs dangerous? Wood frogs typically aren’t dangerous to humans, dogs, cats other pets. While they do produce a noxious skin secretion when threatened, the secretion isn’t potent enough to be of serious harm.

Are wood frogs poisonous to dogs? Wood frogs only have a mildly toxic skin secretion so they are typically harmless to dogs even if eaten. However, their secretion may irritate some dogs, but will not cause any serious harm.

Are wood frogs poisonous to cats? The skin secretions produced by wood frogs are only mildly toxic, so they may slightly irritate but won’t kill or harm most cats.

Conclusion

Wood frogs are unlikely to ever cause you any problems when left alone. If you ever need to handle one, doing it very carefully and washing your hands immediately afterward, should keep you out of harm’s way.

Be mindful of the frog too! Frogs generally do not like to be handled by anything bigger than them. So, it’s a good idea to observe wood frogs from a distance, without physically touching them.

Image credits: mnerrie, via inaturalist.

Ezra Mushala

Hi, my name is Ezra Mushala, i have been interested animals all my life. I am the main author and editor here at snakeinformer.com.

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