Gray wood frog (Batrachyla leptopus)
|Synonyms:||Hylodes brevipes, Hylodes cardioglossa, Hylodes chonotica, Hylodes fitzingeri, Hylodes gracilis, Hylodes granulatus|
|Size||Length: 39 mm (2)|
The gray wood frog is classified as Least Concern (LC) on the IUCN Red List (1).
The gray wood frog (Batrachyla leptopus) was discovered by Charles Darwin in the dense forests of Valdivia, Chile. It has a brown upper body and limbs, marked with darker brown and brownish-yellow bands, which are most conspicuous on the limbs and feet. By contrast, the belly is pale, and marked with brown dots (3).
The gray wood frog inhabits temperate forests of Chile and Argentina, from Concepcion in central Chile south to Coihaique. It is found between altitudes of 50 and 1,000 metres above sea level (1). While this species is mostly distributed on the mainland, small isolated populations also persist on Chiloé Island (4).
Although mainly found in humid, temperate southern beech (Nothofagus) forests, the gray wood frog also occupies bogs, marshes and wetlands surrounded by forest, and the shores of ponds and lakes within swampland (1).
An inconspicuous species, the presence of the gray wood frog is betrayed by the mating calls of the adult males, which are made from within a burrow or crevice amidst moss or under fallen logs (1) (5). During mating, (termed amplexus in frogs and toads), the male gray wood frog clambers upon the back of the female and grasps the body just in front of the hind legs. The female then produces a jelly-like cluster of around 90 eggs, which are fertilised by the male (6). The eggs are deposited in humid sites under logs or stones, close to a body of water, where they remain until the onset of rain causes the area to become flooded, at which point the eggs hatch and the tadpoles develop in the floodwater (1) (6). While this breeding strategy prevents the eggs from being exposed to aquatic predators, it relies upon rains occurring. Nevertheless, in the absence of rain the embryos can arrest development, and survive for up to 40 days on their abundant yolk reserves (2).
Owing to the gray wood frog’s wide distribution and presumed large population, it is not currently considered to be globally threatened. This species’ habitat has, however, been degraded or cleared for exotic tree plantations and human settlements in some locations, particularly in the northern part of its range (1).
The gray wood frog occurs in many protected areas, and even in areas where it does not receive protection, it is tolerant of a degree of deforestation (1). Nevertheless, it is but one of a number of remarkable frog species found in the temperate Northogfagus forests of southern Chile (4), a habitat which is strongly in need of protective legislation in order to preserve the unique wildlife that it contains (1).
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IUCN Red List (April, 2009)
- Diaz, N.F., Sallaberry, M. and Valencia, J. (1987) Microhabitat and reproductive Traits in Populations of the Frog, Batrachyla taeniata. Journal of Herpetology, 21: 317 - 323.
Bell, T. and Darwin, C.R. (1843) Reptiles Part 5 No. 2 of The Zoology of the Voyage of H.M.S. Beagle. Smith Elder and Co, London. Available at:
- Formas, J.R. and Brieva, L.M. (2000) Population genetics of the Chilean frog Batrachyla leptopus (Leptodactylidae). Genetics and Molecular Biology, 23: 43 - 48.
- Penna, M. and Veloso, A. (1990) Vocal diversity in frogs of the South American temperate forest. Journal of Herpetology, 24: 23 - 33.
- Formas, J.R. (1976) Descriptions of Batrachyla (Amphibia, Anura, Leptodactylidae) tadpoles. Journal of Herpetology, 10: 221 - 225.