Rana graeca is a brown frog with a relatively short and rounded snout. The body is relatively wide and flat. Individuals reach a snout-vent length of 70 to 80 mm. The pupil is horizontal. The tympanum is often hard to distinguish and is 3/5 of the diameter of the eye. The body is gray, brown, reddish, yellowish or olive, and dark brown spots are often present. There are also individuals with large bright fungus-like spots on the back. The throat has dark pigmentation with a characteristic bright stripe through the middle. The belly is whitish and mostly unspotted.The males turn black-brown in the mating season. Their skin gets jelly-like due to subcutaneous lymph accumulations (Noellert and Noellert 1992).
Distribution and Habitat
Country distribution from AmphibiaWeb's database: Albania, Bulgaria, Greece, Montenegro, Serbia
The species is distributed in four countries of Europe: Greece, Bulgaria, former Yugoslavia and Albania. In Greece, it is present almost throughout the mainland, in Bulgaria in the south and west of the country, in former Yugoslavia in the Skopje region, Montenegro, Herzegovina, Bosnia, and parts of Serbia, while in Albania it inhabits most of the country. Climate plays an important role in the distribution. The species prefers relatively cold and wet areas, while avoiding areas with severe and long winters, aswell as those being dry and hot. The habitat of the species includes clear streams, springs and small rivers, having running water during the whole year and located mostly in deciduous and mixed forests, but also in hilly and mountainous valleys. In those biotopes, Rana graeca lives near water throughout the year, rarely venturing far from it, and then usually at night or after the rain, when the air moisture is high. However, there are some reports of individuals found at a remarkable distance from water. In Greece the species occurs from 240 up to 1400 m, in Bulgaria from 280 up to 1150 m. In Albania and former Yugoslavia from 200 up to 2000 m. Very occasionally, specimens have been found at lower altitudes, even at sea level (Gasc 1997).
Life History, Abundance, Activity, and Special Behaviors
Adults live along the banks of streams and springs and flee into the water when frightened. There is only one reproductive period per year in Rana graeca. The reproductive period begins shortly after hibernation in February and ends in April. Male Rana graeca call under or above the water surface, being aggregated in pools formed by the current or at places near the banks where the water runs slowly. Dark crevices in the bank under roots or stones are preferred calling and mating sites (Asimakopoulis et al 1990). Males call mainly during the night, but they can also call during the day depending on the water temperature. Amplexus generally lasts about 48 hours. The egg masses are attached to the roof of a cavity. One egg mass can contain 200 to 2000 eggs. The eggs are 2-3.5 mm in diameter with a gelatinous envelope of 4-7 mm. Observations suggestthat males may guard the eggs for a while (Noellert and Noellert 1992). Newly hatched larvae are 9 mm in length and grow up to 45 mm in 2 to 3 months, although low water temperatures may cause development to slow significantly. Sexual maturity is reached after the third hibernation (Engelmann et al 1985).
Trends and Threats
Rana graeca is abundant in medium and high altitude areas, in Greece, especially in Epeiros and Macedonia regions. In Bulgaria it is referred to as abundant at altitudes between 400 and 700 m. In Albania and former Yugoslavia between 300 and 1000 m. The species is not directly endangered. However, habitat destruction caused by forest fires and drainage effects may lead to a severe decline of the species' populations. The danger has been more obvious in Greece in recent years where the dimensions of both problems, forest fires and drainage effects, are continually increasing (Gasc 1997).
Possible reasons for amphibian decline
General habitat alteration and loss
Drainage of habitat
Asimakopoulos, B., Sofianidou, T. S., and Schneider, H. (1990). ''Reproductive and calling behavior of the Greek Frog Rana graeca (Amphibia, Anura) in Greece.'' Zoologischer Anzeiger, 225, 133-143.
Engelmann, W.-E., Guenter, R., and Obst, F. J. (1985). Lurche und Kriechtiere Europas. Neumann Verlag, Leipzig.
Gasc, J.-P. (1997). Atlas of Amphibians and Reptiles in Europe. Societas Europaea Herpetologica, Bonn, Germany.
Nöllert, A. and Nöllert, C. (1992). Die Amphibien Europas. Franckh-Kosmos Verlags-GmbH and Company, Stuttgart.
Written by Arie van der Meijden (amphibia AT arievandermeijden.nl), Research associate, Museum of Vertebrate Zoology, UC Berkeley
First submitted 1999-10-04
Edited by Meredith J. Mahoney (2002-05-25)
Species Account Citation: AmphibiaWeb 2002 Rana graeca: Greek frog <http://amphibiaweb.org/species/5042> University of California, Berkeley, CA, USA. Accessed Nov 18, 2019.
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Citation: AmphibiaWeb. 2019. <http://amphibiaweb.org> University of California, Berkeley, CA, USA. Accessed 18 Nov 2019.
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