Leptodactylus savagei

The Smoky Jungle Frog is definitely one of our most impressive frogs. Its enormous size and girth will consistently draw gasps of shock and, at times, horror from our guests on The Night Tour.

Smoky Jungle Frogs contain a powerful toxin in their skin called leptodactylin. If you were to pick this frog up, it would immediately begin secreting large amounts of mucous from its skin. If the person handling the frog is unfortunate enough to have a cut or scrape on their hands, it will start stinging right away and they would probably end up with a very nasty rash. If you were in a closed room with someone handling the frog, it may vaporize its toxins and cause sneezing, swelling of the eyes, and runny nose even to innocent bystanders.

These very large frogs are also very formidable predators. They prey on a variety of frogs, even large tree frogs such as Gladiator Tree Frogs (Boana rosenbergi) and Masked Tree Frogs (Smilisca phaeota).  They detect calling males and home in on their location using their keen sense of hearing.

Incredibly, they can also feed on snakes up to 500 millimeters in length! It is also the only frog in Latin America known to make scorpions a part of their diet. Once, while on The Night Tour, we came across a Smoky Jungle Frog struggling to ingest a very large Jack-O-Lantern Land Crab, about as big as the frog itself. Other prey items may include: very large insects, bird nestlings, lizards, and bats.

During their mating season, Smoky Jungle Frog males will generally call from swampy areas, the edges of ponds, or marshes. Sometimes they will call from their underground burrows. Their call is a very loud "whroop!" which is repeated every few seconds. Males are easily distinguished at this time because their arms become very swollen and they develop spikes near each thumb and two on their chest. The spikes are used in territorial clashes with other males as well as to better grasp females during mating.   

If a female is attracted into a male's territory they will mate right there.  Females normally lay about 1000 eggs.

In the picture, on the right, of  two Smoky Jungle Frogs mating, the female is below the male nearly submerged in the foamy nest. The tip of her snout and right eye is barely visible.

The foamy nest will protect the eggs from predators and dehydration and will also provide the tadpoles with some nutrition after they hatch. Once they do hatch, tadpoles will normally be washed out of the nest during a heavy rain. They develop in stagnant bodies of water where they feed on other tadpoles, including their own species, frog eggs and vegetable matter. It will take the tadpoles about 28 days to complete their metamorphosis and emerge from the water as tiny froglets. If they can avoid predation, Smoky Jungle Frogs may live up to 15 years.

References:

Beletsky, L.  2005  Travellers' Wildlife Guides Costa Rica  Interlink Publishing

Janzen, D.  1983  Costa Rican Natural History  University of Chicago Press

Leenders, T.  2001  A Guide to Amphibians and Reptiles of Costa Rica  Zona Tropical

Savage, J.  2002  The Amphibians and Reptiles of Costa Rica   University of Chicago Press