The moor frog (Rana arvalis ) is a slim, reddish-brown, semiaquatic amphibian native to Europe and Asia. It is a member of the family Ranidae, or true frogs.
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TerrestrialTerrestrial animals are animals that live predominantly or entirely on land (e.g., cats, ants, snails), as compared with aquatic animals, which liv...
Oviparous animals are female animals that lay their eggs, with little or no other embryonic development within the mother. This is the reproductive...
Jumping (saltation) can be distinguished from running, galloping, and other gaits where the entire body is temporarily airborne by the relatively l...
Semiaquatic animals are those that are primarily or partly terrestrial but that spend a large amount of time swimming or otherwise occupied in wate...
Hibernation is a state of minimal activity and metabolic depression undergone by some animal species. Hibernation is a seasonal heterothermy charac...
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starts withThis is a small bog frog, characterized by an unspotted belly, a large, dark ear spot, and — often, not always — a pale stripe down the center of the back. They are generally described as a reddish-brown, but can also be yellow, gray, or light olive. Their bellies are white or yellow and they have a "bandit-like" black stripe going from their nose to their ears. They vary from 5.5 to 6.0 cm long, but can reach up to 7.0 cm in length, and their heads are more tapered than those of the Common frog (Rana temporaria ). The skin on their flanks and thighs is smooth, and the posterior part of their tongues is forked and free. They have horizontal pupils, their feet are partially webbed, and their back legs are shorter than those of other species of frogs. The males are different from the females because of the nuptial pads on their first fingers and their paired guttural vocal sacs.
The species has an extensive distribution across Europe. It can be found inhabiting an area stretching from the lowlands of Central and Southern Europe to Siberia, in Austria, Belarus, Belgium, Czech Republic, Denmark, Estonia, Finland, France, Germany, Hungary, Latvia, Lithuania, Moldova, Netherlands, Norway, Poland, Romania, Russian Federation, Slovakia, Slovenia, Sweden, Switzerland, and Ukraine. However, they are believed to be extirpated in Switzerland and possibly in Serbia as well; the records of frogs being in Serbia at all may have been in error. Alsace, France, constitutes the western boundary of their territory. Moor frogs were also confirmed to have been present in East Anglia in the UK, after archaeological remains were found from the 9th century. Furthermore, a historical reference was also found from the 13th century by Bartholomeus Anglicus ("Rana palustres"). The species has been successfully bred in captivity in the UK and a reintroduction has been proposed as part of Celtic Reptile & Amphibian's rewilding plans.
The types of land they can inhabit are greatly varied. They live in tundra, forest tundra, forest, forest steppe, and steppe, forest edges and glades, semideserts, swamps, meadows, fields, bush lands, and gardens. They prefer areas untouched by humans, such as damp meadows and bogs, but they still may be able to live in agricultural and urban areas.
Moor frogs provide a good model for studying local adaptation as they experience a wide range of environments and are relatively limited in their movements. Their restriction in movements implies limited gene flow and facilitates evolution through adaptive genetic differentiation among populations.
Moor frogs will hibernate sometime between September and June, depending on the latitude of the location. Frogs in southwestern, plains areas will disappear later (around November or December) and return earlier (February). Frogs in cold, polar areas, though, will disappear sooner (in September) and return later (in June).
The mating season takes place between March and June right after the end of hibernation. Males form breeding choruses, and their songs sound similar to those of the agile frog, (Rana dalmatina ). Their calls can "sound like air escaping from a submerged empty bottle: 'waug...waug...waug'. Males can also develop bright-blue coloration for a few days during the season.
The spawning happens very quickly and is completed in three to 28 days. The spawn of each frog is laid in one or two clusters of 500-3000 eggs in warm, shallow waters like in ponds.
This species is generally common and often abundant. It faces few major threats and is currently classified as Least Concern by the IUCN. The moor frog may be impacted by the destruction and pollution of breeding sites and adjacent habitats, mostly through urbanization, recreational use of waterside areas, and intensive agriculture. The species does not appear to be notably susceptible to chytridiomycosis, although the fungus has been detected in frogs in Germany.
