Mountain Chicken

[tgampper]

Leptodactylus fallax (Muller, 1926) – Mountain Chicken, Giant Ditch Frog



General Information

Family: Leptodactylidae

Native: Dominica, Montserrat
Extinct: Guadeloupe, Martinique, Saint Kitts and Nevis

Average Size:
Dominica – 12.6 cm SVL (5 in), 171 g mass (6 oz)
Montserrat – 16.7 cm SVL (6.5 in), 436 g mass (15 oz)

IUCN (Red List) Status: Critically Endangered (CR)

Similar Species: Leptodactylus pentadactylus; South American Bullfrog, Smokey Mountain Jungle Frog

Description and Natural History



The Mountain Chicken is one of the largest frogs in the Western Hemisphere, reaching a maximum length of 20 cm (8 in) and a weight of 670 g (24 oz). The back of the frog is a chestnut-brown color, either spotted or barred, with continuous dorsolateral folds running from the eye to the groin. The color becomes a washed out orange along the ventral side.

The frog is terrestrial and found in a variety of habitats – woods, scrub, hillside plantations and river valley palm groves, from sea level to around 430 m (1400 ft). It hides in burrows during the day and is active at night. The diet includes a variety of invertebrates, such as, crickets, gastropods, millipedes, crustaceans and occasionally small vertebrates, like lizards, snakes, frogs and bats.

The mountain chicken calls on rainy nights from April to September along the island’s water courses. The call has a territorial significance. The “whooping” call is made by the dominant male to alert others that he is protecting his nesting burrow. Males will wrestle each other for territory. Once the dominant male is satisfied his burrow is safe, the call changes to a “trilling bark” so he could attract the females in the area. Amplexus, the frog’s mating embrace is axillary, which means the male grips the female just behind the forelimbs. The male will stimulate the female’s cloaca by bringing his hind feet in contact, to encourage fluid excretion. The male then engages in bouts of paddling with both hind legs until the foam nest is completed (about 10 hours). The male will leave soon after the nest is built, leaving the female inside the burrow guarding the nest.

It takes about 45 days for the terrestrial tadpoles to complete their larval development. During this time, the female will leave the nest only for feeding. The foam will keep the tadpoles moist until the froglets emerge from the burrow. The average nest itself contains roughly 35 tadpoles, yet the female will provision over 20,000 unfertilized eggs for them to feed on.

Threats and Population Trends

Human harvesting for food. The national dish of Dominica is the mountain chicken. They are hunted in large numbers both legally and illegally to satisfy the dietary needs of the local people as well as a growing number of tourists. It is very likely the reason that the average size of the frogs is smaller in Dominica is because they are harvested before they reach sexual maturity. The fewer numbers of sexually mature frogs will adversely affect population growth.

Introduced predators. The frogs are subject to predation by invasive species such as, feral pigs, opossums, dogs, and cats.

Habitat loss. The mountain chickens are restricted to the coastal areas of Dominica. Most of the coast is being developed for human activities.

Pollution. Agricultural chemicals and raw sewage are being released in freshwater systems. Fishermen on the island often use a toxic, plant-derived chemical that will paralyze freshwater fish.

Natural disasters. Deforestation and construction have been blamed for flooding and landslides. Since these small islands have active volcanoes, it is not possible to protect the frogs from these eruptions.

Disease. The fungal disease, chytridiomycosis, invaded the island of Dominica in 2002 causing a catastrophic decline in mountain chicken population. The decline is continuing and this species is facing extinction.

Conservation Efforts

Under the IUCN’s Red list, this species’ status is listed as critically endangered, meaning that they are very rare and close to extinction. The governments of Dominica and Montserrat have since passed laws protecting the frog. Public awareness actions have taken place to inform the Dominican public of the magnitude of threat facing their national dish and to discourage illegal hunting. Twelve zoos worldwide are involved in captive breeding programs.

Sources

Daltry, J.C. Mountain Chicken Monitoring Manual. Fauna & Flora International. 2002.

John Fa, Blair Hedges, Beatrice Ibéné, Michel Breuil, Robert Powell, Christopher Magin 2004. Leptodactylus fallax. In: IUCN 2010. IUCN Red List of Threatened Species. Version 2010.1. <www.iucnredlist.org>. Downloaded on 27 March 2010.

Gibson, R.C., and Buley, K.R. “Maternal Care and Obligatory Oophagy in Leptodactylus fallax: A New Reproductive Mode in Frogs.” Copeia. 2004(1). 128-135.

Schwartz, A., and Henderson, R.W. Amphibian and Reptiles of the West Indies: Descriptions, Distributions, and Natural History. Gainsville: University of Florida Press. 1991.

Photos: Terry Gampper - used with permission

Written by: Terry Gampper
Posted: 20 October 2010

[JimO]

Thanks for that post Terry. That is a really cool frog and what a terrible shame that it has been hunted nearly to extinction. Do you know if there are efforts to captive breed and re-introduce the frog to its former range?

[John]

Many thanks Terry. Do you want me to link to this under "Meet the Frog" ?

[tgampper]

Many thanks Terry. Do you want me to link to this under "Meet the Frog" ?

Thanks, John. I would appreciate that.

[tgampper]

Thanks for that post Terry. That is a really cool frog and what a terrible shame that it has been hunted nearly to extinction. Do you know if there are efforts to captive breed and re-introduce the frog to its former range?

Thanks, Jim. Since early 2009, three captive breeding projects have been established in Europe: the Durrell Wildlife Conservation Trust (Jersey, UK), London (UK) Zoo, and Parken Zoo (Stockholm, Sweden). It appears that the London Zoo is the only place in the world with a captive breeding program involving frogs from both Dominica and Montserrat. Unfortunately, chytrid devistated the frogs in Montserrat, save for those at the zoos. Besides the fungus, it is still be hunted for food despite the island government's plea to stop.