Wood frogs are fairly small frogs found from the northeastern quarter of the United States and throughout most of Canada to central and southern Alaska. These frogs have a very varied coloration, but they are typically brown, rusty red, gray, or tan and have bumpy skin. But are wood frogs poisonous?
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 carriers 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.
