Home | Amphibians | The Marine Toad, Bufo marinus (recently re-classified as Rhinella marina) in Nature and Captivity – Part I, Natural History

The Marine Toad, Bufo marinus (recently re-classified as Rhinella marina) in Nature and Captivity – Part I, Natural History

Overview
Recently I wrote about those tiny jewels of the frog world, Latin America’s poison frogs (Article Part I and II).  Today I’ll introduce you to a behemoth that is largely their direct opposite, the massive Marine Toad – at once one of the world’s most interesting and troublesome of amphibians (actually, the people who have transported it around the globe are troublesome, not the toads!).

Physical Description
This largest of the world’s toads may reach 10 inches in length.  Generally brown to tan in color, some individuals show a yellow or reddish tint.  One that I received from a friend working on Guam was clad in several shades of yellow and quite beautiful. Enormous paratoid (poison) glands extend from behind the eyes to the sides of the body.  The body is squat and rounded in profile.

There seems to be a great deal of variation in size among different Marine Toad populations, with the true giants that came out of Colombia and Suriname in the 1960’s and early 70’s being rarely seen in the trade today.  I examined a great many in working in Venezuela, and most were in the 4-6 inch range (this comports with locally published accounts).  Florida’s introduced animals are relatively small in size (but large as toads go), as are those in south Texas.

Me with Large Marine ToadThe photo accompanying this article shows me holding a large female that was collected, I believe, in Colombia.  She has inflated her lungs with air to prevent my swallowing her (fat chance!) – the stick is to discourage the two 18 foot long anacondas that share her exhibit from attempting to swallow me!

Range and Habitat
People are sometimes surprised to learn that the Marine Toad is a US native, but those living in southern Texas are indeed part of a naturally occurring group.  Florida and Hawaii’s large populations are introduced.

From Texas, this toad range south from southern Sonora, Mexico through Central America to central Brazil, Amazonian Peru and Bolivia.  Marine Toads have been widely introduced and are well established in Florida, Hawaii, Taiwan, Japan, New Guinea, Australia, and throughout the islands of the Caribbean (i.e. Puerto Rico, Antilles, St. Lucia) and the South Pacific (i.e. Fiji, Guam).

Marine toads dwell in a wide variety of habitats, including open forest, overgrown scrub, grasslands, fields and marshes.  They adjust well to disturbed sites and are common in agricultural areas, suburbs and urban parks (i.e. within Miami, Fla.).  Several I observed on Tortuguero, Costa Rica, crossed a 30 foot stretch of mowed lawn each evening to feed near my bedroom’s outdoor light.

Status in the Wild
Generally common within natural range and usually very common, to the point of being a harmful invasive, where introduced.

Diet
Marine Toads consume nearly any creature that fits within their cavernous mouths – centipedes, roaches, beetles, millipedes, earthworms, land crabs, spiders and other invertebrates, frogs, lizards and snakes.  Mice, birds and similar creatures are taken when encountered, but stomach analysis of toads in the Venezuelan llanos (grasslands) showed this to be a rare occurrence in that habitat.

This is one of only a very few frog species to consume non-living food items (African Clawed Frogs, Xenopus spp. will take carrion and, amazingly, Izecksohn’s Treefrog of Brazil eats berries).  While in Costa Rica, I regularly observed a large toad eating dog food (after pushing open a screen door to get at it!), and those kept by co-workers at the Bronx Zoo ate salad set out for tortoises.  Field reports from New Guinea indicate that Marine Toads there rely upon vegetation as food during the dry season.  Stomach analysis of wild individuals indicates that they also will take carrion (chicken and fish) and the eggs of other Marine Toads. 

In addition to hunting by sight, these toads apparently utilize olfaction (rare for a terrestrial frog) as well.

Reproduction
Marine ToadAn extremely flexible reproductive biology accounts for this animal’s success as an invasive species.  Unlike most amphibians, it can reproduce throughout the year in favorable habitats, in brackish (saline) water and in waters containing high fish populations.

Large females may lay as many as 36,000 eggs, attached in strings to aquatic vegetation.  In contrast to most frogs, both eggs and tadpoles are protected by virulent toxins.  The tadpoles take 10 days to 6 months to transform, depending upon temperature and diet, and can survive 10 hours without water.  They consume algae, dead plants, carrion and each other, and generally out-compete or eat the tadpoles of other species.  Newly transformed toads disperse widely and often establish new limits to existing ranges.

Miscellaneous
Marine toads are likely the world’s most widely introduced amphibian (American Bullfrogs and Greenhouse Frogs are close competitors for this title).  They are generally transported to agricultural areas to control insect pests, a strategy that rarely works.  In Australia, for example, the toads seldom catch cane beetles, their intended prey – the beetles dwell high above the ground and the toads do not climb.

Introduced populations expand rapidly, consume native animals and out-compete others.  On Oahu, Hawaii, 148 introduced toads multiplied to over 100,000 in a 2 year period.

The Marine Toad’s toxins are powerful and complex.  Threatened toads will lower their heads and attempt to bring the poison-containing paratoid glands in contact with the attacker.  In Australia, 3 species of quoll (a medium-sized mammal) and 8 species of monitor lizards prey upon the toads and are declining due to deaths caused by the toad’s skin toxins.  Dingoes, snakes, foxes, dogs and other animals have also expired after eating Marine Toads.

Most predators occurring within the Marine Toad’s natural range leave them strictly alone.  I have, for example, housed them with green anacondas for many years – despite that fact that the snakes will avidly consume other frog species.  However, several snake and possibly bird species have evolved toxin immunities and prey upon them.  In Australia, White-Tailed Water Rats have apparently learned to avoid the skin toxins by flipping the toads and chewing through the belly skin to reach the internal organs.

Marine toads are quite responsive to their surroundings.  Captive animals anticipate food upon seeing their keepers, and those living in developed areas learn to gather under street lights to capture insects.

Marine Toads make responsive long-lived pets – I’ll cover their care next time.   Until then, please write in with your comments and questions.  Thanks, Frank.

A field report detailing some of the unusual foods and other items found in the stomachs’ of free-living Marine Toads is posted at:
http://www.jstor.org/pss/1564710

 

29 comments

  1. avatar

    i have always loved toads and am infactuated with the cane/marine toad. i have been unsuccessfully trying to buy one 10 inches snout to vent for a year now. i found a florida variety 8 inches but i want one from colombia or suriname 10 in or more. can someone please help me ? i will be very grateful. contact this website for my e-mail. cane toads are beautiful and need love and affection.

  2. avatar

    Hello, Frank Indiviglio here. Thanks for your interest in our blog.

    Unfortunately very large marine toads, which do often originate in Suriname and Columbia, are rarely imported these days. However, amphibian availability changes from day to day, and you really never know what to expect –animals common in the trade disappear, while others long gone show up as laws change or collectors/breeders switch their focus. Your best bet would be to monitor the lists of the better-known reptile dealers from time to time. If you are near our store, please visit to see what we have available, and speak with our Reptile Room staff as well.

    Marine toad populations vary quite a bit as to size potential…2 of the largest I worked with were collected in Suriname in the late 60’s, and lived well into their 20’s. An 8 inch animal from the introduced Florida population, as you mention, is actually quite large. I’ve collected marine toads in Florida, Venezuela, Costa Rica and St. Croix, but have yet to come across one larger than 7 inches snout-vent.

    Please let me know what you find.

    Best regards, Frank Indiviglio.

  3. avatar

    my toad does not eat mice and will not eat crickets if im watching

  4. avatar

    Hello Sean, Frank Indiviglio here. Thanks for your interest in our blog.

    It is better that your toad does not take mice, no need to use them; health problems of result. The toad may be more likely to eat in front of you if you put the food in towards evening. A Night-Viewing Light is useful for watching your pet after dark, when it is likely to be more active.

    It’s very important to supply your toad with a varied diet…it will not do well, long term, if fed only crickets. This can be difficult if the toad does not eat while you are present, but there are a few techniques you can try. Please write back if you need further information.

    Best regards, Frank Indiviglio.

  5. avatar

    Aloha, I live on O’ahu and have three large cane toads that come to swim in my water pond every night. I think that they hide within the rocks during the day. What is your advice on allowing them to remain there or not? I have large pond fish and cats but none have bothered the other. Are the toads helpful by eating bugs or just taking advantage of the “swimming pool”? I’m tempted to relocate them elsewhere. Thanks!

  6. avatar

    Hello Laura, Frank Indiviglio here. Thanks for your interest in our blog. Hawaii sounds so good right now…this has been the coldest, wettest spring/summer NYC has experienced in years!

    Interesting question…cane toads are so well established there that others will likely move in if you relocate the residents. They do consume a great many insects (although, in Australia, not the cane beetles that the original importers hoped they would battle – the beetles live well above the ground, out of reach of the toads!).

    The cane toads won’t bother fish, although they will likely lay eggs in your pond at some point. Cats seem to learn quickly to avoid the toads – they likely get a taste of their bad tasting skin toxins at some point and remember, even pass along the info to their young. The main problem posed by the toads (in addition to their eating and out-competing native reptiles, insects and amphibians) has to do with predators that grab and swallow them quickly. In Australia this is a real concern for some monitor lizards and snakes, but I don’t believe any Hawaiian animals would be affected in that way.

    Please let me know if they breed – I’m very interested in Hawaii’s introduced animals. Have you ever run across any of the Jackson’s chameleons or blue poison frogs that are said to be established on Oahu and some of the other islands?
    Good luck and please keep me posted.

    Best regards, Frank Indiviglio.

  7. avatar
    johnny toad lover

    MY 11 INCH CANE TOAD ATE A 3 INCH TURTLE AND A 4 INCH SUNFISH,HE PULLED BOTH RIGHT OUT OF THE WATER, HA HA,IT WAS GREAT WATCHING HIM EAT BOTH OF THESE EXCEPT IT TOOK HIM AWHILE TO DIGEST AND SHOOT OUT SOME OT THE POOR LITLE PET TURTLE. JOHNNY D, PA, USA

  8. avatar

    It’s interesting that the toad could take them right out of the water…I’ve observed marine toads to feed on hatchling side-necked turtles (Podocnemis vogli) in the field, but they always captured them on land, as the turtles made their way to water after hatching. How deep was the water?

    That’s some large toad you have there – is 11 inches the snout-vent length or length with legs extended? I’d be interested in it’s weight also, if you have a moment.

    Good luck and please keep me posted.

    Best regards, Frank Indiviglio.

  9. avatar

    Aloha Frank,
    Thank you so much for your quick reply. The toads are interesting because they are so bizarre looking. If they lay eggs in the pond, will my pond fish eat the eggs and receive the toxins they contain? I have three goldfish, two of which are 7″ long, and a Plecostomus about 5″ in length. I don’t want the fish to be harmed but it would be interesting to watch the eggs.

    Also, what does the toad dung look like? I find single, black pellets around the yard that are .5″ wide by 1.5″ long. Is this from the toads?

    To answer your question about the Jackson’s chameleons and blue poison frogs, yes my next door neighbor has found a J. chameleon in her yard but I’ve seen no sign of the frogs. The region I live in (leeward side, Ewa Plain) is likely too dry for them.

    I plan on capturing the toads to check measurement and weight. Are the females larger than the males? One toad is larger than the other two.

    Thank you, again, for the information.
    Aloha,
    Laura

  10. avatar

    Hello Laura, Frank Indiviglio here. Thanks very much for writing back concerning the chameleons and poison frogs.

    Female cane toads are usually larger than males. Cane toads vary greatly in size from population to population – the real giants usually come from Guyana and parts of Columbia, but much has to do with the environment and food base as well. I’d be very interested to hear about the sizes of those you come across.

    Very good point re the toad eggs …sorry I didn’t mention it earlier. The eggs of many toads native to the US mainland are non-toxic, but those of the cane toad (and their tadpoles) are highly toxic and could theoretically kill your goldfish if consumed. The jelly around the eggs often dissuades fish from sampling them – I know of a population of American bullfrogs that breeds in a koi pond here in NY – but it is a potential risk.

    The pellets you describe are not likely from the toads. Usually their waste products are passed in a liquid or semi-liquid state, and they break down rapidly. Of course, if any animal could adjust the composition of its droppings, it would be the cane toad!.. but I’ve not seen any frog produce formed pellets.

    Thanks again for your feedback and for raising the point concerning egg toxicity.

    Good luck and please keep me posted.

    Best regards, Frank Indiviglio.

  11. avatar

    besides crickets what would be the ideal meal for my toad he is about 3-4 inches

  12. avatar

    Hello Sean, Frank Indiviglio here.

    Thanks for your interest in our blog.

    Marine and other toads should be given as much variety as possible. During the warmer months, try to provide wild caught invertebrates often – sow bugs, moths, grasshoppers, beetles, non-hairy caterpillars and so on. Avoid brightly colored insects and fireflies (possible toxicity), those that may potentially bite or sting (large ants, wasps). The Zoo Med Bug Napper is a useful insect trap.

    Earthworms, collected or purchased, can be used as a major part of the diet year-round, and are preferable to crickets as a staple food.

    In the cooler months, use canned insects to supplement commercially available species (most toads take these from a feeding tongs readily). In addition to crickets, you can purchase waxworms, roaches and mealworms. It’s best to set up a mealworm colony (please write in if you need details) and to use newly-molted (white) mealworms only. Once the mealworms transform into beetles, they can be used freely.

    Be sure to feed your crickets well – please see my article Prepared Diets for Crickets for more information. If you type “collecting insects” into the search box at the upper left hand corner of the article, you will find several articles on collecting insects for captive amphibians.

    Good luck and please keep me posted.

    Best regards, Frank Indiviglio.

  13. avatar
    Denise in Honolulu

    Is it possible for a Bufo to make a loud noise that sounds like a UFO is landing inside the house? If so, why? The noise comes and goes. Two nights ago this UFO type noise kept me up for hours then woke me again at two a.m. I finally called the police last night when it started up again just after eight. A neighbor said it is a Bufo.

  14. avatar

    Hello Denise, Frank Indiviglio here.

    Thanks for your interest in our blog and unique question.

    I’ve heard many “unearthly” noises growing up in New York City, but I can’t claim landing UFO’s as one of them (at least, not that I know of!). Cane toads can make quite a racket when breeding (the males call to attract females), but it’s usually identifiable as a frog-like noise, and you usually will hear many at once. Also, at this time they gather near water – you wouldn’t likely hear calling from anywhere other than a pond, pool or puddle.

    You can listen to a recording of cane toad mating calls at:
    http://sounds.bl.uk/View.aspx?item=022M-WAMPHX0036XX-0900V0.xml

    A tiny treefrog know as the coqui has been introduced to Hawaii from Puerto Rico. Millions call at once, and their sound is unfamiliar to residents when the frogs invade a new area. These little guys will be harder to spot than cane toads, and often call from trees and bushes.

    Please keep me posted…I’m interested to know what turns up.

    Happy hunting!

    Best regards, Frank Indiviglio.

  15. avatar
    johnny toad lover

    hi frank, you wrote to me back on 12-4-8. two months later, i got my wish, a giant cane toad from venezuela, i was told. yes, he is 11 inches long snout to vent and weighs 4 1/2 pounds, a monster. but you won’t believe where i got him and the price. he came from england and cost me a total of 500 us dollars. i had to pay a plane ticket for him, ha ha, but he is well worth it. boy, he sure gets around. his name is kane(king kane). i wish i knew his age because i love him and hope he stays around for a long time. he loves to eat and eats everything. my poor neighbor shut down his pond. after he saw me with kane, i guess he figured out what happened to his fish and turtles. sincerely, johnny toad lover in pa

  16. avatar

    Hello Johnny, Frank Indiviglio here.

    Thanks for the feedback.

    That’s quite an impressive animal (and cash outlay!) you have there…at or near the record and larger than any I’ve seen, even back in the late 60’s when some monsters were coming out of then French Guiana and Columbia.

    The main thing to watch for with such a large specimen is cleanliness; they produce a great deal of ammonia which can cause fatalities if allowed to remain in the terrarium or water bowl. Also, please avoid “testing its limits” as regards food…do not offer unusually large meals and never feed live rodents. Despite what you may see on the inter net, they are not designed to catch mice; study after study has shown that invertebrates comprise nearly 100% of the natural diet. Even dead mice can cause problems as regards impacted hair. A pinky or 2 every 6 weeks or so will do no harm, but no more than that. De-clawed crayfishes are a great calcium source; shiners and other fishes can be offered every 2 weeks or so as well.

    Good luck, enjoy and please keep me posted.

    Best regards, Frank Indiviglio.

  17. avatar
    johnny toad lover

    frank, for years i have read about a 15 inch 6 pound cane toad in a sweden zoo, supposedly the biggest one in the world. but i have never been able to find out what zoo so i can write them and get a picture of him. would love to see him live on youtube. kane is 11 inches and he is big, wow, can you imagine 15 ? i might make an offer. i am looking for another 11 inch cane toad for a friend for kane but no luck. wish i could find a legal animal exporter in ven, col, sur, or guy as i assume the biggest are in those 4 countries. write back soon, johnny and kane

  18. avatar

    Hello Johnny, Frank Indiviglio here.

    Thanks for the feedback.

    I’m not sure about the Sweden story, may have heard it…if you find the name of the zoo, I could likely check it out for you.

    Even zoos have trouble getting large toads these days…it seems as though really huge ones may be limited to specific populations within certain countries, and may have been collected out, or, as often happens, situations change and those areas are no longer accessible. I handled hundreds in south-central Venezuela, in llanos country, and never found one over 5 inches snout-vent; same holds in south Florida; those I found along the edges of rain forest habitat in eastern Costa Rica were moderate, 7-8 inches, but neither I nor any coworkers even uncovered any giants.

    Large importers will sometimes keep an eye open for you, if you can establish a relationship, but I had no luck that way when looking for animals for a zoo a few years back.

    Good luck and please keep me posted.

    Best regards, Frank Indiviglio.

  19. avatar

    Hi, Frank.

    Yesterday afternoon I saw something large hopping in my lawn. At first I thought it might have been a large toad. As I approached I thought it might have been a baby rabbit.

    Upon it’s first fearful hop I realized, indeed, that it was a Rhinella marina. The largest I have ever seen here in South West Florida.

    I quickly captured it in a bucket and took photos with a tape measure and in my latex-gloved hand.

    5 inches from shout to vent. Knowing that it is an invasive species I decided to keep it as a pet.

    I happened to have a 60 gallon (cracked) aquarium in storage -former reef tank that got chipped on a corner and ruined- and figured it would make for a decent terrarium environment for my new house guest.

    I am no stranger to housing reptiles but from what I understand this is one of the “easier” to maintain.

    I have a clay flower pot large enough for the toad to hide from the aquarium lighting and a proper soil with a drainfield. I plan to introduce some small plants in the near future.

    I have read about a varied diet. Should I “dust” the inverts with calcium / multi-vits and how often? I am using lighting designed for reef growing.

    I might also introduce some red wrigglers (compost worms) and use this as a habitat for them as well since toad might like to eat some decomposing veggies and earthworms as well.

    What kind of plant-life (available in Florida) do you suggest that will help create a mini ecosystem? And also what other inverts should I add as a regular diet?

    I used to feed Cuban Anoles (another invasive species here in Florida) to my snakes … should I worry about tossing one or two in each week? The anole can feed on the inverts that are dusted and gut-loaded and toad can eat the occasional lizard …

    Please advise, and thank you very much for your feedback.

  20. avatar

    Hello Scott, Frank Indiviglio here.

    Thanks for your interest in our blog.

    Marine toads adapt well to captivity, but bear in mind that an adult will produce a great deal of waste; ammonia poisoning via dirty substrate/water is a concern. A wild caught adult might take some time to calm down as well. A 60 gallon tank will make a good enclosure.

    Plants and soil are difficult – they crush most plants and soil complicates cleaning. An easily-removed and/or washable substrate, such as sphagnum moss or even a terrarium liner, is preferable.

    If you provide a varied diet, supplementing 1-2x weekly should be fine; alternate between Reptivite with D3 and Reptocal.

    The light you describe may be too intense – high levels of UVB can be detrimental to many amphibians. A zoo med 2.0 would be a safer option.

    Marine toads take vegetables only during food shortages – salad taken incidentally by some I cared for was barely digested upon excretion. No need to provide plant-based foods. Earthworms are a very nutritious food item.

    An anole on occasion is fine in theory, but there is a chance of parasite/disease transmission. This is not much of a concern as regards most wild caught inverts, but may be with lizards.

    Moths, most beetles, earthworms, roaches, grasshoppers, katydids, cicadas, grubs, crickets are among the most useful wild-caught invertebrates to use.

    Be sure to provide a water bowl with dechlorinated water; change daily.

    Good luck and please keep me posted.

    Best regards, Frank Indiviglio.

  21. avatar

    Hi i just moved to florida and i was at a bar and it was about 11pm and i walked around the side of the building and there were around 20 toads which is not unusual i hear but then i saw one that was the size of a rabbit and was wondering what it might have been it wasnt a bull frog im from wisconsin and have seen bull frogs and thats what my roommate tried to tell me but i know it was a toad but what kind

  22. avatar

    Hello Brandon, Frank Indiviglio here.

    Thanks for your interest in our blog. You almost certainly saw a Marine Toad; they have been introduced to Florida through the pet trade (they occur naturally in south Texas, and range south to central South America). Size varies among populations – those in Fla. tend to be fairly small, but not always, as you observed.

    Good luck – Florida’s summer must be quite a change from Wisconsin!, and please keep me posted.

    Best regards, Frank Indiviglio.

  23. avatar

    hi i have a large surinam marine toad, 9inch vent to snout, with huge glands.
    how long does it take for them to hit 11inch vent to snout.
    what is the growing rate with these toads.

  24. avatar

    Hello Tom, Frank Indiviglio here.

    Thanks for your interest in our blog. Size in marine toads seems very much dependent on genetics, not so much on food supply as is the case with many other frogs, and they vary greatly from population to population.

    I handled hundreds while on field research in Venezuela (central llanos ) and never found one over 6”; further south, along rainforest edges, they grow larger; same when I was in Costa Rica, although there were a few that topped 7-8”. Those in northern Mexico and southern Texas are usually small (as marine toads go), as is the introduced population in Fla.

    The real giants used to come out of Surinam and Columbia in the 60’s and 70’s; a few years ago I searched for some large ones for a public exhibit and came up empty. I’m surprised any are coming out of Surinam these days, thought exports had been halted – 9” is quite large by today’s standards, but no real way to predict if or when the frog will get larger. Please keep me posted when you can, I’m interested to hear what happens.

    Please let me know if you need any further information. Good luck, enjoy and please keep me posted.

    Best regards, Frank Indiviglio.

  25. avatar

    Hi again, i know someone that has a 12inch surinam marine toad, if you have a email address i can send you the picture, she is an incredible size, you wont believe your eyes.
    thanks

  26. avatar

    Hello Tom, Frank Indiviglio here.

    Thanks for the offer; I’d love to see it. When time permits, please email to findiviglio@thatpetplace.com

    Best regards, Frank

  27. avatar

    I have sent the pictures, hope you like.
    thankyou

  28. avatar

    Hello Tom, Frank Indiviglio here.

    Thanks for the very impressive photos; I’ll get back to you, may do another article and would love to highlight this animal,

    Best regards, Frank Indiviglio.

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About Frank Indiviglio

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Being born with a deep interest in animals might seem unfortunate for a native Bronxite , but my family encouraged my interest and the menagerie that sprung from it. Jobs with pet stores and importers had me caring for a fantastic assortment of reptiles and amphibians. After a detour as a lawyer, I was hired as a Bronx Zoo animal keeper and was soon caring for gharials, goliath frogs, king cobras and everything in-between. Research has taken me in pursuit of anacondas, Orinoco crocodiles and other animals in locales ranging from Venezuela’s llanos to Tortuguero’s beaches. Now, after 20+ years with the Bronx Zoo, I am a consultant for several zoos and museums. I have spent time in Japan, and often exchange ideas with zoologists there. I have written books on salamanders, geckos and other “herps”, discussed reptile-keeping on television and presented papers at conferences. A Master’s Degree in biology has led to teaching opportunities. My work puts me in contact with thousands of hobbyists keeping an array of pets. Without fail, I have learned much from them and hope, dear readers, that you will be generous in sharing your thoughts on this blog and web site. For a complete biography of my experience click here.
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