How To Tell If A Frog Is Poisonous
There are over 4,700 species of frogs inhabiting every continent in the world except Antarctica. They come in different sizes and colors. Some are arboreal, some terrestrial, and some aquatic. But are frogs poisonous? And if so, how dangerous are they?
It may surprise you to learn that frogs (and toads) have toxins on their skin. These toxins are a frog’s defense mechanism against predators. They range from mild to dangerous.
Because toxins are a substance that can be absorbed or ingested, it’s considered poison. Scientists refer to this type as “bio-toxins” or “natural toxins” because it is produced by a living creature.
This post is meant to show you how to identify the poisonous frogs and teach you a little about bio-toxins.
Don’t worry – most frogs are harmless to humans. Regardless, there are a few species that actually are dangerous. I will show you how to identify them based on their appearance and location in the world. Aside from toxins, amphibians are known to carry salmonella – but more on this later.
- Frogs produce toxins (making them “poisonous”).
- Most are harmless to humans.
- They’re known to carry salmonella.
Identifying The Dangerous Frogs
The “dangerous” frogs are the ones carrying toxins that are potentially life-threatening when touched or ingested. They’re the ones you should avoid. Luckily, there aren’t too many of them and they’re easy to identify.
They come from the Dendrobatidae family; commonly known as poison dart frogs. These brightly colored frogs inhabit the rainforests of Central and South America. While pretty to look at, they contain a powerful alkaloid toxin known as Batrachotoxin (BTX), which works by causing paralysis when entering the bloodstream.
Batrachotoxin is likely the most famous amphibian toxin due to the popularity of dart frogs (Dendrobatidae).
What Poison Dart Frogs Look Like
The most defining feature of poison dart frogs is their color. There are over 100 species of poison-dart frogs; all of which have varying colors, patterns, and sizes. Below are two pictures for examples.
Notice the different colors. The one on the left is black, having blue and green speckles on its legs and a yellow-green stripe on the back. The one on the right is mostly yellow. Can you spot the similarities? The general shape and build are the same. Both have a pointed nose and black eyes.
Poison dart frogs have different patterns and colors but they all have the same general shape with few exceptions.
The deadliest frog belongs to the Phyllobates Genus. Its scientific name is Phyllobates terribilis, which roughly translates to “dreadful leaf-climber”. The common name for this species is Golden poison frog. It’s believed that adult golden poison frogs contain enough poison to kill two full-grown elephants.
Only a handful of species within the Dendrobates family are considered deadly to humans. In fact, at the time of writing this, I was unable to find a single published report of someone dying as the result of a frog.
Researchers believe poison frogs produce toxins after eating alkaloid-containing insects. In fact, hobbyists have successfully kept dart frogs as pets for years. Because they do not have access to alkaloid-containing insects in captivity, they’re not poisonous.
Interesting Facts About Colorful Animals
In the animal world, bright colors mean “stop!” “I’m dangerous”. This system tends to work, as bright colors often suffice in deterring would-be predators from attacking.
A term for this warning coloration is Aposematic. Example: “the dart frog has aposematic coloration.”
Not all colorful frogs are as deadly. Some species mimic poisonous frogs in appearance, all the while having a very weak toxin in comparison. Others simply have bright colors due to years and years of adapting to a certain region.
Utilize the illustration and photos above to see what poison-dart frogs look like. This, along with what you learned, will help you to tell if a frog is poisonous or not. More accurately, it will help you identify the dangerous ones.
Where Poison Frogs Live
Knowing where poison-dart frogs live is useful because it helps you determine whether or not you should be concerned. They’re adapted to a warm, high-humidity, rainforest environment and can’t survive in much of the US, Canada, or the UK.
Poison Dart Frogs are endemic to Central and South America. They thrive in the rainforests where humidity is high.
From parts of Bolivia and Brazil in South America, up to Nicaragua in Central America. In addition to this, Green and Black Dart Frogs were introduced into Hawaii.
Up until now, we’ve covered the most dangerous frogs, what they look like, and where they’re located. However, frogs aren’t the only poisonous member of the Anura order. Toads have toxins, too.
Poisonous Toads: Bufotoxin
There are some differences between true frogs and true toads, but that’s a topic for another post. Because people often use the words “frog” and “toad” interchangeably, I’ve decided to include them in this article.
Yes, toads are poisonous too. They secret a toxin from parotoid glands which are located just behind their eyes. It’s called Bufotoxin.
By the way, “true toads” are found in the Bufonidae family. Hence the name “bufotoxin”.
Bufotoxin is relatively weak in comparison to that of dart frogs (Batrachotoxin). Regardless, it’s worth mentioning here because toads are abundant and can be dangerous to small animals like cats and dogs.
Toads are found all over the United States, Canada, United Kingdom, and other parts of the world. And much like frogs, the potency of their toxins differs from one species to the next.
Toads carry bufotoxin in the glands behind their eyes (see the picture below). It has a milk-like appearance.
Touching it can result in irritation of the skin. Rubbing your eyes after getting the toxin on your hand is undoubtedly worse. Swallowing it would be unlikely because, well, people generally don’t go around swallowing live toads. Some reactions include a strong irritation, vomiting, allergic reaction, and general discomfort.
You’ll be happy to know that toads cannot excrete the substance at will. It has to be squeezed out. This is why animals are more at risk than humans. A playful cat or dog might fall victim to a toad if they bite and squeeze out the toxin.
Two particular species to watch for are Cane Toads and American Toads. Cane toads are an invasive species to Florida. They’re large compared to most amphibians. American Toads (Anaxyrus americanus) include a few sub-species and they inhabit Central and Eastern United States.
Here are some tips when dealing with toads. Be careful not to squeeze their parotoid glands. Remember, this is where the bufotoxin is stored. It has a milk-like appearance. If you get some on your hands, thoroughly wash your hands with soap and water. Keep an eye on your pets. Cats and dogs find toads interesting and bufotoxin is more harmful to small pets.
Salmonella: It’s not just poison you have to worry about.
In general, it’s best not to handle frogs. Handling amphibians is frowned upon because it is stressful for the frog. Not only that, their skin is semi-permeable, so any chemicals on your hands will likely be absorbed into the frog. Those chemicals can be harmful or deadly to the frog.
Another reason, and the focus of this section, is that frogs and toads can carry the bacteria called Salmonella . It’s thought to be spread through their droppings. Either by direct or indirect contact, you might be at risk!
This is especially important for young children, who are notorious for catching wild frogs, toads, and reptiles. I did it when I was young. My two kids love catching frogs.
Children under the age of 5 are more likely to develop severe symptoms caused by salmonella, according to the NY State Department of Health. No one wants salmonella, so do yourself a favor and be careful. If you come into contact with any reptile or amphibian, be sure to thoroughly wash your hands with soap and water!
I hope this page has been helpful in identifying the harmful, poisonous frogs! The following section will answer some common questions.
Frequently Asked Questions
This section aims to provide short, precise answers to popular FAQs regarding the toxins in amphibians. Please refer to the main portion of the guide for more information on identifying the potentially harmful frogs.
It’s thought that all frogs produce toxins, whether mild or strong. Because “poison” is defined as a harmful substance that is absorbed (by touch) or ingested (swallowed), toxins are poison. Technically speaking, all frogs are poisonous. Most, however, are not harmful to humans and some are barely harmful to animals.
We learned at the beginning of this post that some scientists call these toxins “bio-toxin” or “natural toxins” because they’re produced by living creatures (frogs).
The most common symptoms of poisonous frog toxins can include a strong irritation, vomiting, allergic reaction, and general discomfort.
If you come into contact with a frog, be sure to thoroughly wash your hands with soap and water.
All frogs produce toxins and toxins are considered a type of poison. So technically speaking, tree frogs are poisonous. However, most of them are not dangerous to humans.
Tree frogs are arboreal meaning they live in trees. Their pads (like fingers or hands) are specially developed for climbing. They’re the frogs you can find seemingly stuck to the underside of leaves, on your windows and other vertical-oriented surfaces.
Two of the most common types of tree frogs in the United States are Gray Tree Frogs and American Green Tree Frogs. Both produce a mild toxin that is barely noticeable, even to small animal predators.
Some species of frogs are semi-arboreal. This means they spend part of their lives in trees and the other part on the ground (terrestrial). A few poison-dart frogs fall into this category. For example, it’s not uncommon to see them on plants, namely bromeliads, a few feet off the jungle floor. While they’re not considered tree frogs, they can be dangerous. They’re mostly found in Central and South America.
While most frogs are virtually harmless, there are still risks. Those risks include exposure to harmful bacteria, such as salmonella, and the toxins on their skin. Most are harmless but some are not.
Yes, young children are more likely to develop severe symptoms caused by salmonella.
The Golden Poison Frog is considered the world’s most toxic amphibian. However, recent findings suggest the title of the deadliest frog goes to a venomous frog (yes, I meant to type venomous) known as Bruno’s casque-headed frog.
TLDR; How To Identify Poisonous Frogs
If you’re looking to learn how to identify poisonous frogs, this guide is a great place to start. We’ve outlined the most common ways of identifying dangerous frogs as well as what to do if you come into contact with one.
In summary, there are only a few dangerous frog species in terms of toxicity. They’re known as poison dart frogs and they are mostly located in Central and South America. Also, cane toads and other large toads can be deadly to small pets like cats and dogs.
Frogs can be harmful not just because of their poison, but also through the spread of bacteria like salmonella. Be sure to wash your hands thoroughly if you come into contact with any amphibian!
- Hofrichter, Robert. The Encyclopedia of Amphibians. Gardners Books, 2000., p. 112[↩]
- Mermin, Jonathan, et al. “Reptiles, Amphibians, and HumanSalmonellaInfection: A Population‐Based, Case‐Control Study.” Clinical Infectious Diseases, vol. 38, no. s3, 2004, pp. S253–61. Crossref, doi.org/10.1086/381594.[↩]
- “Salmonella Infection from Frogs, Turtles and Lizards.” New York State Department of Health, www.health.ny.gov/diseases/communicable/zoonoses/salmonella/amphibian_reptilian_questions_and_answers.htm. Accessed 25 Feb. 2022.[↩]
hi just wanted to say thanks for the facts
Hey! I’m from Brazil, I had some issues with a frog appearing in my room from nowhere during the night. I have no idea about how he did come in, but I’m a little relieved after reading your article, seems like here is a poison frog’s area, but hopefully, this one is not one of them. Thanks!
Poison dart frogs tend to stay near the ground! I’m glad you found this post helpful.
Can tadpoles be poisonous? Another question… are tadpoles tht correct name for both baby frogs and baby toads? Thanks
Tadpole is correct for frog and toad. Frogs and toads are in order Anura, which is a part of the Amphibia class. Tadpole, polliwog, etc. Some people call them Toadpoles as well, which is fine.
It’s believed that dart frog tadpoles become toxic after their mother passes toxins through unfertilized eggs. You can read more about this here.
I saw a frog in my room though I guess it’s from previous rainstorms and I don’t know if it’s poisonous , it’s small and very dark in colour
Ever heard of the Bufo Alvarius?
Yes! A great example of a Poisonous Toad.
Hey, I live in the UK so I know we don’t have alot in the way of exciting frogs (I don’t think anyway) but I want to thank you for this super interesting post! It was a good read 🙂 I learnt alot!
Thanks, Heidi! Glad you found this helpful.
I found a solid white frog with pinkish feet on my pool wondering what kind it is and if it is poisonous it was very unique and beautiful but I had to get a net and relocate it just in case it was poisonous.lives in North Carolina
Interesting! I’m trying to research something that fits the bill for this. Perhaps a “little grass frog” or a “squirrel treefrog” although height of them are solid white with pink feet. Perhaps the pool’s water/sunlight had an effect on the frog.
Thanks for posting this, I found it very interesting and it helped me know what frogs I don’t want to touch. This helped me a lot because I love frogs! Thank you!
Glad it helped, Alex!
I’m nearly 70 now. As a boy, many of us would spend a Saturday catching frogs. A friend of mine caught a brightly colored frug. Long story, short; he placed it in with his other frogs and the next day the other frogs had killed it. Is that normal for an invasive species to be killed by the native species? Pottsville, PA
Yes! That’s normal. Especially frogs of different species. Smaller frogs often get picked on or killed by larger frogs, even of the same species.
Hey John, Pottsville, PA here found a tiny rust colored frog and it looks like it has armor plating. This little guy was not round but shaped like it actually had plating. More geometrical or rectilinear. Not scales. Could you please tell me what type of frog this is? Is it poisonous? Could it possibly be poisonous to dogs? I should have taken a picture of it, but didn’t have my cp at the time. Your feedback and answers will greatly appreciated.
Hi Peggy! I’m sorry, I can’t think of a frog that looks like what you described in PA. Spring peepers can have a rust color but they have smooth skin.
I caught a toad a little while back and brought it home and he seems to be doing really well but I’ve tried to give him other bugs to eat like flies and other things but he only eats crickets and one time he ate a butterfly but I’m just wondering what are some other things i should try to feed him
I recommending reading this page on what frogs eat. It covers foods for captivity as well.
Just wanted to thank you for the interesting read and your thoughtful answers! I randomly found your page because my puggle found a bull frog (I think – round, brownish/grayish/greenish cute fella) in our yard and was was barking away at it. We brought our dog inside and my husband put gloves on and helped the frog to safety. We live in AZ next to a golf course – what kind of frog/toad do you think it was?
Hey no problem, Kathleen! Thanks for the nice comment! It’s hard to tell. It may have been a bullfrog or possibly a toad. How big was it? Here is a page with a list of possible frogs living in Arizona. I hope this helps!
A small dart frog, as if green hopped onto my hand. I whisked it off immediately. But it left a liquid on my skin … Is this frog safe!?
You should certainly wash your hands and see a doctor if you’re feeling weird. Where in the world do you live? Are you sure it was a dart frog?
I live in Florida and my room has a balcony that I like to open sometimes. It’s been raining a lot and I usually hear a frig on the sill but it’s at night mostly and I don’t think much of it. Tonight as I lay in bed the frog hoped on my pillow and now I’m scared I may be infected or have been infected by the frog as it managed to get into my room. What do I do.
Wash your covers/pillow and maybe consider getting a window screen? You most likely had a tree frog jump on your bed. They’re fairly harmless and probably the only type of frog that could reach your balcony! If you’re feeling weird, give your doctor’s office a call and see what they say.
If a from was light green and yellow spots is it poisonous????
It’s hard to tell what type of frog you’re talking about based on that description alone. What part of the world did you find him in?
Hey, I’m from northern Kentucky and there was a frog I believe on my porch last night that I handled and then put in the grass. I wasn’t able to identify the frog or identify what kind of frog it may have been, but I’ve been super on edge about it and worried about it being poisonous and me not realizing it.
Don’t worry too much. The chances of a poisonous frog being in Kentucky are slim-to-none. The only thing you need to worry about is salmonella. Wash your hands afterwards and you’ll be fine!
I have 2 dogs one is a German Shepherd the other is my baby she is a rat terrier who sees a frog and won’t stop til she gets it or I catch it and release it back outside thank God my dogs have not come in contact with them we have American tree frogs everywhere here in southern Florida and huge toads that I know is dangerous for my fur babies
Great article! What are some examples of brightly colored frogs which are not poisonous? I am writing a paper about dishonest signaling and this would be an interesting example.
All frogs are mildly toxic to some degree. The Allobates zaparo is one that mimics more toxic species meanwhile it is not very harmful itself. Check out this article for more information.
Hi and thank you for the interesting article.
I am interested in knowing about brightly colored frogs that are not poisonous, can you please name one?
They’re all mildly toxic to some degree. Allobates zaparo is a species which isn’t nearly as harmful as the Phyllobates Terribilis for example. Aside from poison-dart frogs you’ve got species like the Red-Eyed Tree Frog which has bright blue, orange, red, and green colors. RETF toxins are mostly harmless to humans but they might be irritating to a small animal.
If your frog very small is it bad to keep it?
The size isn’t necessarily a problem. If the frog was wild, you shouldn’t keep it. Opt for a captive-bred frog instead!
Hi. Years ago I spent time in the remote part of the State of Sao Paulo, Brazil. I came upon a huge frog or toad living in, near a pond. It was at least 1 foot in length, green and beige.
The Brazilians warned against anyone touching it. Do you know what it might have been.
My only guess is a bullfrog or a large “True Toad” (Bufonidae family), although they wouldn’t be that big. Bullfrogs can get pretty big but they’re not exactly dangerous either. There are poison-dart frogs in brazil but they’re not that big. I’m sorry, Lisa, I’m at a loss for what kind of frog/toad they were talking about. Goliath frogs grow up to 12″ in length but they’re native to Africa.
Hello, I’m from Texas and there is always a small green frog hanging around at our door and I was wondering if you can let me know if it could be poisonous please. I have an app that identifies plants and animals with pictures and it had said the frog was a Holarctic Tree Frog but I am not sure if it is poisonous and if I should stay away from it.
Hello, Dennise. The frog hanging out around your door is (probably) an American Green Tree Frog. They’re native to Texas (mostly the eastern parts of Texas) and they’re small, green frogs.
Most frogs have a mild amount of toxin but its rarely noticeable to humans. The chances of you running into a dangerous, poison-dart frog in Texas are slim-to-none. It’s too hot and dry for them.
Anyway, American Green Tree frogs are harmless 🙂 I don’t recommend grabbing one unless you need it. Touching one will hurt the frog more than you. But, if you have to, make sure to wash your hands afterwards. Frogs can transmit salmonella through their droppings – read the last two paragraphs of this page for more information.
i saw a frog outside of my door ond my mom held it. it was small and green.
I was unable to say for sure if the sierrian tree frog is harmful to my small dogs if ingested as my yard is teeming with them.
I want to know what frogs and Tods in Florida are bad for you ….and I want to know what they look like and if you add the good frog to thx this was helpful
No problem, Kerin – I’m glad this was helpful! I’m not very familiar with the different types of frogs in Florida but I feel confident in saying that cane toads are probably your biggest worry. They’re an invasive species, mostly a threat to pets and animals (especially dogs). Click here for info about frogs in Florida. Some parts of Florida might have the correct environment to support poison-dart frogs but I haven’t read any reports of this happening.
Hi I’m from Indiana and a frog living in soil sprayed pee into my eye and I flushed it with water and wondered if you had any suggestion to weather I should be at any panic . I’m from Indiana in the USA .
Hey, Anthony. I’m sorry to hear that happened to you. Amphibians can carry salmonella and it’s often transmitted through their droppings. Don’t panic, though; not all amphibians have salmonella. I’m not qualified to give medical advice but I’d recommend calling your doctor to see what they recommend.