Mountain chicken (Leptodactylus fallax)

Mountain chicken fact file

• Description
• Biology
• Range
• Habitat
• Status
• Threats
• Conservation
• Find out more
• Glossary
• References
• Print factsheet

Mountain chicken description

One of the world’s most threatened frogs, the oddly-named mountain chicken (Leptodactylus fallax) is so called because its meat is said to taste like chicken. This curious species is also one of the largest frogs in the world, with adult females growing up to remarkable lengths of 21 centimetres ⁽²⁾.

The mountain chicken is highly variable in colour, with the upperparts varying from a uniform chestnut-brown to being barred or even spotted ⁽²⁾. The colour becomes more orange-yellow on the sides of the body, and pale yellow on the underparts ⁽²⁾. A black line runs from the snout to the angle of the mouth, and the upper legs often have broad banding ^{(2) (3)}. The mountain chicken also has a distinctive, dark-outlined fold from the back of the head to the groin, and large, conspicuous eyes with dark pupils and a golden iris ^{(3) (4)}.

The body of the mountain chicken is robust, with a large head and well-muscled legs ⁽³⁾. The male mountain chicken may be distinguished from the female by its smaller size, and by the black ‘spur’ on each of its thumbs, which are used to clasp the female during amplexus (the mating embrace) ⁽³⁾. 

Also known as

Dominican white-lipped frog, giant ditch frog.

Synonyms

Leptodactylus dominicensis.

Size

Snout-vent length: up to 21 cm ⁽²⁾

Weight

c. 700 g ⁽³⁾

Mountain chicken biology

A sit-and-wait predator with a voracious appetite, the gluttonous mountain chicken consumes almost anything that can be swallowed whole. It is well camouflaged against its habitat and remains still for long periods of time before ambushing its prey, usually at night ⁽³⁾. Its diet is highly varied, but it is thought to be strictly carnivorous, largely consuming crickets, although it also eats millipedes, insects, crustaceans and even small vertebrates, such as other frogs, snakes and small mammals ^{(3) (4)}. During the day the mountain chicken resides in burrows which it digs into moist soil ⁽³⁾.

The mountain chicken has a highly unusual method of reproduction, as unlike most other amphibians which breed in water, this frog breeds in underground burrows around 50 centimetres deep. The breeding season starts towards the end of the dry season, usually in April when there are heavy seasonal showers, and continues to August or September ⁽³⁾.

At the start of the breeding period, the male frogs compete to gain access to preferred nesting sites by wrestling and making loud ‘whooping’ calls from forest paths and undergrowth clearings ^{(2) (3)}. The winning male occupies a nesting burrow and emits ‘trilling barks’ to attract a female mate ⁽²⁾. Once a breeding pair is formed, the male and female engage in amplexus, and the female is stimulated to release a fluid, which the male makes into a foam with rapid paddles of its hind legs. Once the nest is built, which takes 9 to 14 hours, the male leaves the burrow to defend it from intruders, while the female lays the eggs ^{(2) (5)}.

After the larvae have hatched, the female mountain chicken lays up to as many as 25,000 unfertilised eggs upon which the larvae feed. The young froglets take around 45 days to develop, and during this time the female continuously renews the foam, only leaving the nest to feed ⁽²⁾. Eventually 26 to 43 froglets emerge from the nest, with the timing of this coinciding with the onset of the wet season, when there is an abundance of food ^{(2) (3)}.

The mountain chicken reaches maturity at around 3 years, and has a lifespan of approximately 12 years. Mature females only produce one brood per season, but male frogs may father the offspring of more than one female ⁽³⁾. 

Mountain chicken range

The mountain chicken was once found on many of the eastern Caribbean islands, but is now restricted to just Dominica and Montserrat. It once occurred for certain on Guadeloupe, Martinique, Saint Kitts and Nevis, but is now extinct on these islands, and it may have also inhabited Saint Lucia and Antigua. The species was also unsuccessfully reintroduced to Jamaica and Puerto Rico ⁽¹⁾.

Today, the mountain chicken is largely restricted to the western side of Dominica and the Centre Hills of northern Montserrat, having been lost from much of the rest of the island due to recent volcanic eruptions ^{(1) (3)}. It is also found on the eastern side of Dominica, but the species’ origin there is unclear and it may have been introduced to the area ⁽³⁾.

Mountain chicken habitat

The mountain chicken is found in a variety of moist habitats, including dense secondary forest and scrub, hillside plantations, palm groves in river valleys, ravines and flooded forest ^{(2) (3) (4)}. It is most commonly found near streams and springs, and is rarely found in grasslands ⁽³⁾. On Dominica it is most abundant at lower altitudes, although it occurs up to 400 metres, and is found up to 430 metres on Montserrat ⁽¹⁾. 

Mountain chicken status

The mountain chicken is classified as Critically Endangered (CR) on the IUCN Red List ⁽¹⁾.

Mountain chicken threats

An unfortunate victim of hunting, disease, natural disasters and habitat loss, the mountain chicken population has recently undergone catastrophic declines, estimated at around 80 percent since 1995 ^{(1) (2)}. On Dominica, this Critically Endangered frog is favoured for its meaty legs, which are cooked in traditional West Indian dishes, and which are in fact the country’s national dish ⁽⁶⁾. Annual harvests were thought to be taking between 8,000 and 36,000 animals before a ban on hunting was introduced and, as a result of this exploitation, the population on the island is thought to be near extinction ⁽¹⁾.

The mountain chicken is particularly vulnerable to overharvesting as it has a relatively small brood size, limiting its ability to recover from heavy losses. The removal of breeding females is particularly damaging, as the tadpoles are dependent upon the females for food and moisture. The species’ large size, loud calls and tendency to sit in the open also makes it a particularly easy target for hunters ⁽³⁾.

The mountain chicken has also lost huge areas of its habitat to agriculture, tourist developments, human settlements and, on Montserrat, volcanic eruptions. On Dominica, the species is largely confined to coastal areas where there is great demand for land for construction, industry and farming, while on Montserrat, volcanic activity since 1995 has exterminated all populations outside of the Centre Hills ^{(1) (3)}. Human encroachment upon the species’ habitat has also brought it into contact with a range of pollutants, including the highly toxic herbicide Gramazone, which is known to kill birds and mammals. Predation from introduced mammals, such as feral cats, dogs, pigs, rats and opossums, is also a relatively new threat to the species on Dominica ^{(3) (7)}.      

Perhaps the greatest, and least understood, threat to the mountain chicken today is the deadly fungal disease chytridiomycosis ⁽¹⁾. This disease, which has wiped out many amphibian populations across the globe, became established on Dominica in 2002, and frog populations on the island declined by approximately 80 percent within 2 years ^{(2) (7)}. The Dominican population is now so small that there may not be enough individuals to ensure the survival of the mountain chicken on this island. The fungus was introduced to nearby Montserrat in 2009, potentially via infected frogs hiding in shipments of fruit and vegetables. Like on Dominica, huge mountain chicken declines of 80 to 90 percent occurred. By July 2009, the last remaining healthy population of mountain chickens on Montserrat had succumbed to the disease ⁽⁷⁾.

Mountain chicken conservation

Hunting of the mountain chicken was banned on Dominica in the late 1990s, although a three month open season was declared at the end of 2001, and hunting was not fully prohibited until 2003 ^{(1) (3)}. Public awareness programmes have also been implemented to inform the Dominican public of the threats the mountain chicken faces and to try to discourage hunting ⁽¹⁾.  

Following the catastrophic volcanic eruptions on Montserrat, it became clear that dedicated conservation measures were needed if the mountain chicken was to be saved from extinction. In July 1999, the Durrell Wildlife Trust took six male and three female frogs to Jersey Zoo as part of a captive breeding study. Additional frogs have since been taken from disease-free areas, and the species has readily bred in captivity, with a number of other zoos achieving further breeding success ⁽⁶⁾. These captive frogs now form the basis of a safety-net population should the species become extinct in the wild ⁽⁶⁾. In addition, since January 1998 the Montserrat Forestry and Environment Division, in partnership with Fauna and Flora International, have been monitoring the species’ population ⁽²⁾.

In response to the devastating spread of the ‘chytrid’ fungus on both Dominica and Montserrat, conservation focus has been upon preventing the extinction of the mountain chicken in the wild. The threat of chytridiomycosis has taken priority over other conservation efforts for this species, such as habitat protection and the control of invasive predators ⁽⁷⁾.

When the chytrid fungus was first discovered on Montserrat in 2009, 50 frogs were immediately flown from the island and entered into the bio-secure breeding programme already in place. After the last remaining healthy population in Montserrat became infected, a field trial using anti-fungal treatment directly in the wild also ensued. Scientists aim to ensure the survival of the mountain chicken population on Montserrat by a combination of field study, capacity building and species reintroductions ⁽⁷⁾. The mountain chickens are breeding well in captivity ⁽⁸⁾, and successful and carefully monitored reintroductions took place in 2011 and 2012 ⁽⁷⁾. Although, as expected, some of the released frogs became infected, they were generally looking healthy and were calling ⁽⁹⁾.

On Dominica, a captive-breeding facility has been built, equipped with the facilities to analyse frog skin swabs for the presence of chytridiomycosis. Invertebrate prey stocks have also been established to satisfy the captive-bred frogs’ insatiable appetites. In 2010, five frogs were captured and placed in the facility, and, later in the year, a juvenile mountain chicken was found, indicating that the wild population on Dominica is also breeding. Mountain chickens bred in the facility will be released back into the wild to replenish Dominica’s wild population ⁽⁷⁾.

There are still many unanswered questions regarding the deadly chytridiomycosis, but there is a dedicated team of people working to ensure the persistence of the wild mountain chicken on both Dominica and Montserrat ⁽⁹⁾.

View information on this species at the UNEP World Conservation Monitoring Centre.

Find out more

Further information on the mountain chicken and its conservation:

• Durrell Wildlife Conservation Trust:
  http://www.durrell.org/Animals/Amphibians/Mountain-chicken/
• Zoological Society of London - Meet the mountain chicken:
  http://www.zslblogs.org/2011/08/16/meet-the-mountain-chicken/
• BBC Nature - Mountain chicken:
  http://www.bbc.co.uk/nature/life/Leptodactylus_fallax
• AmphibiaWeb - Leptodactylus fallax:
  http://amphibiaweb.org/cgi-bin/amphib_query?where-genus=Leptodactylus&where-species=fallax

Find out more about conservation on Montserrat and Dominica:

• Kew Royal Botanic Gardens - Enabling the people of Montserrat to conserve the Centre Hills:
  http://www.kew.org/science-research-data/directory/projects/UKOTs_Montserrat_Conserve_Centre_Hills.htm
• RSPB - Montserrat Programme:
  http://www.rspb.org.uk/ourwork/projects/details/198131-montserrat-programme
• Montserrat National Trust:
  http://mninationaltrust.com/
• San Diego Zoo Wildlife Conservancy - Dominica Nature Park:
  http://www.sandiegozooglobal.org/what_we_do/conserving_habitat/dominica_nature_island/

Authentication

This information is awaiting authentication by a species expert, and will be updated as soon as possible. If you are able to help please contact:
arkive@wildscreen.org.uk

Glossary

Amplexus

The mating position of frogs and toads, in which the male clasps the female around the back or waist.

Carnivorous

Feeding on flesh.

Crustaceans

Diverse group of animals with jointed limbs and a hard chitinous exoskeleton characterised by the possession of two pairs of antennae, one pair of mandibles (the mouthparts used for handling and processing food) and two pairs of maxillae (appendages used in eating, which are located behind the mandibles). Includes crabs, lobsters, shrimps and barnacles.

Feral

Previously domesticated animals that have returned to a wild state.

Fertilisation

The fusion of gametes (male and female reproductive cells) to produce an embryo, which grows into a new individual.

Invertebrates (invertebrate)

Animals with no backbone, such as insects, crustaceans, worms, molluscs, spiders, cnidarians (jellyfish, corals, sea anemones) and echinoderms.

Larvae

Stage in an animal’s lifecycle after it hatches from the egg. Larvae are typically very different in appearance to adults; they are able to feed and move around but usually are unable to reproduce.

Secondary forest

Forest that has re-grown after a major disturbance, such as fire or timber harvest, but has not yet reached the mature state of primary forest.

Vertebrates

Animals with a backbone, including mammals, birds, reptiles, amphibians and fish.

References

1. IUCN Red List (February, 2013)
   http://www.iucnredlist.org/
2. AmphibiaWeb (September, 2010)
   http://amphibiaweb.org/cgi-bin/amphib_query?where-genus=Leptodactylus&where-species=fallax
3. Daltry, J.C. (2002) Mountain Chicken Monitoring Manual. Fauna and Flora International, Cambridge, and the Forestry and Wildlife Division, Dominica.
4. Schwartz, A. and Henderson, R.W. (1991) Amphibians and Reptiles of the West Indies: Descriptions, Distributions and Natural History. The University of Florida Press, Florida.
5. World Association of Zoos and Aquariums - Giant ditch frog (September, 2010)
   http://www.waza.org/en/zoo/choose-a-species/amphibians/frogs-and-toads/leptodactylus-fallax
6. Durrell Wildlife Conservation Trust - Mountain chicken (September, 2010)
   http://www.durrell.org/Animals/Amphibians/Mountain-chicken/
7. Saving the Mountain Chicken (February, 2013) www.mountainchicken.org
8. The Zoological Society of London - Rescued frogs breed for the first time (February, 2013)
   http://www.zsl.org/conservation/news/rescued-frogs-breed-for-first-time,985,NS.html
9. IUCN - Mountain chicken frogs back in Montserrat (February, 2013)
   http://www.iucn.org/about/union/members/?9772/Mountain-chickens-back-in-Montserrat