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The Natural History and Captive Care of the Smokey Jungle Frog – Part 1

Smokey Mountain FrogI’ve studied and cared-for a great many frog species in my time, but count the robust Smokey Jungle Frog, also known as the South American Bullfrog (Leptodactylus pentadactylus), as one of the most beautiful and mysterious of all.  I’ve been very fortunate in having bred this frog in captivity, and today will examine its natural history and reproduction.  I’ll move on to diet and its unique habits in Part 2.

Range

This frog occurs from Honduras and northern Nicaragua through Venezuela to French Guinea and south to southern Columbia, Ecuador, northern Brazil, Peru and Bolivia.  Due to its secretive nature, the southernmost limits of its range are not well known.

Habitat

Usually found in lowland rainforests near slow-moving streams, the Smokey Jungle Frog is sometimes encountered far from permanent water sources.  It commonly frequents dimly-lit, heavily-vegetated habitats.

Although it resembles semi-aquatic species in body-form, this frog is largely terrestrial.  Adults shelter in burrows at the bases of trees, and are entirely nocturnal.  The burrows are utilized on a long term basis.  Juveniles are reportedly active by day, but those I’ve raised have ventured out only after dark.

Description

With a snout-vent length of 7.4 inches, this is one of Latin America’s larger Anurans.  Variably colored in gray, tan and reddish-brown, and with irregular black markings, it is spectacular in appearance.  Adult males have thick forearms, 2 black spines on the chest and a black spine on each thumb.

Juveniles, more brightly-colored than adults, are usually a shade of rust or reddish-brown.

Reproduction

Males call from the water’s edge during the rainy season, which occurs from May-November, depending upon location; territorial calls are issued from within burrows.  The females lay approximately 1,000 eggs while grasped by the males in pectoral amplexus (below the forearms).

Male Smokey Jungle Frogs use their powerful rear legs to whip the jelly surrounding the eggs into a frothy mass of sperm, jelly, skin secretions, air and water.  This nest surrounds the eggs and is deposited in a natural (or possibly self-dug) depression in the ground, usually at the water’s edge.  The tadpoles are washed into waterways by the rain.

Terrestrial Nests

Interestingly, nests are sometimes deposited far from the water’s edge, and metamorphosis is achieved entirely on land.  In these instances, the tadpoles do not leave the nest until they have transformed into frogs.  It is assumed that they feed upon the nest itself, as well as upon eggs and each other, while developing.  The tadpoles are very resilient to desiccation, and are kept moist by the frothy nest.

Rearing the Tadpoles

Smokey Jungle Frog tadpoles are large, reaching a length of 2.5-3.5 inches before transformation.  They initially feed upon algae and the nest itself, and gradually add aquatic invertebrates, carrion and tadpoles to their diet.

I’ve bred this species several times, with the tadpoles always being moved into water upon hatching.  They fed ravenously upon algae, soaked greens, dead minnows and blackworms, and transformed at 2.5 – 2.8 inches in length.  Dead tadpoles were consumed by tank-mates, but I have not determined if actual predation occurred.

In the future I hope to raise a clutch in the nest, without water, in an effort to better understand their unique breeding strategy.

Further Reading

Please see this field report on a closely related frog for more on terrestrial nesting.

Don’t miss this Video of wild Smokey Jungle Frogs!

 

6 comments

  1. avatar
    Daniel Rodriguez

    I have captured a pair of this tadpoles and yes they are predators among their tankmates, I made the mistake to mix them up with some other no identified tadples and I saw may Leptodactylus tadpoles eating the other larvae.

    • avatar

      Hello Daniel, Frank Indiviglio here.

      Thanks for the feedback and the interesting observation; I’ve never kept them with other tadpole species, so only saw them preying upon each other. I really appreciate the first-hand observation, as do the other readers – please keep them coming!

      Good luck, enjoy and please keep me posted.

      Best regards, Frank Indiviglio.

  2. avatar

    Frank, thanks for your article. It’s one of very few I found online about this species. I brought one home today from a reptile show I attended (the guy was desperate to get rid of it, so I took it). I’ve never seen this species before, and knew I needed to research it before deciding whether to adopt it out or keep it for my own programs.

    My husband and I both handled her (apparently female), and fortunately have not had any rash develop. Is this mild toxicity possibly diet-based, similar to poison dart frogs? Thoughts on that?

    If I retain her for my own programs, what would be the best setup. Based on your article, I’m thinking a large, deep rubbermaid tub filled with a combination of peat moss and sphagnum moss, kept damp. Feed a variety of inverts and small rodents. Am I on the right track? Suggestions?

    Thanks for the education,
    Bonnie Keller

    • avatar

      Hello Bonnie, Frank Indiviglio here.

      Thanks for your interest in our blog and the kind words. Not much work has been done on their skin toxins, but they seem not to be diet-related, as long term captives seem to retain them.

      Please see Part II of this article for diet info; you can increase the pinkies above what is recommended there to 1-2 per month for an adult. Do not use furred rodents; earthworms excellent. You might also find this related article of interest.

      Sphagnum is fine; peat tends to be easily swallowed. You can clear off a bare spot for feeding earthworms, as the frog may eat with people present, or by day.

      I would not recommend this species for programs requiring a visible animal or handling – they remain hidden all day and are very stressed by transport; handling should be avoided unless absolutely necessary.

      Some amazing new info on a close relative has come to light recently; please check here for details.

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

      Best regards, Frank Indiviglio.

  3. avatar

    Frank, as someone who has been in the herp hobby for 15+ years, I’m stunned that I haven’t run into you before. I read several of your blog posts just now and I’m thrilled to see that you post ideas that are both common sense and scientifically sound. I operate VA Reptile Rescue, Inc., and used to help run the forums on another large reptile website – actually two of them.
    Anyway, I offered the frog a dozen or so crickets tonight that I’d just purchased from the local reptile show today. She gobbled them up immediately. I absolutely love your article about feeding invertebrates to animals that naturally feed on invertebrates. To me, this just makes evolutionary sense. An animal that has evolved to eat a diet of ______, (fill in the blank) should be fed a diet of _____ (same item.) Mother nature knows best. I have a friend (a biologist!) that insists on switching over his eastern hognoses to rodents because of the decline of toads… :::sigh::: I have a number of articles on my website that I’d love your critique on – especially the one on feeding commercial diets. I read your post about feeding canned insects, and I have used them when they were given to me by folks who were bringing their animals to the rescue. My question has always been, though, why grasshoppers aren’t available for live purchase the way that crickets are. I’d much rather get a box of big locusts to feed my larger invertebrate eaters (savannah monitors, for instance), than feed cooked ones. Pressure cooking is great, and does trap in the juices, but basic biochem shows that the enzymes present in raw foods are broken down by cooking. Those enzymes may be a vital reason for dietary issues in captive animals that are fed altered diets.
    I appreciate the time you obviously spend on these responses, and will look for your reply when you have the chance. I’m sure I’m not the only person who wants to pick your brain…
    Sincerely, Bonnie Keller (VA Reptile Rescue, Inc.)

    • avatar

      Hello Bonnie, Frank Indiviglio here.

      Thanks so much for the kind words; glad to be of use.

      Fine work you’re involved in. I’d be happy to look over articles that you would care to forward. Some of my articles may work well as basic care sheets for specific animals, would be pleased to help out if needed. There are several hundred posted…I can forward specific links if needed, which may be faster than the search engine.

      Locusts are available commercially, but more commonly in Europe; I’ve not checked local sources recently. I’ve raised grasshoppers from nymphs – easy providing you can ID a food source for the species (some are specialists, but most are not) and can provide enough of it – I’ve rarely seen animals eat so much! Easy to imagine the devastation wrought by huge swarms. However, large scale breeding is difficult as eggs of most temperate species need a “winter”, adults need lots of space, specific sex ratios in some cases. I believe Elke Zimmerman gives a good account in her classic Breeding Terrarium Animals.

      Important to research nutritional needs as you suggest; in some cases substitutions are necessary, difficult in others…i.e. we lost a great many Proboscis monkeys and silvered langurs at the Bx Zoo until a source of mangrove leaves, and a replacement biscuit, were found. Unfortunately, matching is usually not possible in any event – so many factors affect nutritional value of inverts, so even if you are collecting the right species, their diet matters; most insectivorous herps consume dozens if not hundreds of species, vary by season, etc – stomach content studies are of great value; usually only published in prof journals but I keep track as much as possible. Looked into this a bit with Horned Lizards… all ants are not created equal. But, we do what we can…

      Good luck, enjoy and please keep me posted.

      Best regards, Frank Indiviglio.

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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