Moor Frog
The Moor Frog is a slim, reddish-brown, semi-aquatic amphibian
Amphibians , are a class of vertebrate animals including animals such as toads, frogs, caecilians, and salamanders. They are characterized as non-amniote ectothermic tetrapods...

 native to Europe
Europe is, by convention, one of the world's seven continents. Comprising the westernmost peninsula of Eurasia, Europe is generally 'divided' from Asia to its east by the watershed divides of the Ural and Caucasus Mountains, the Ural River, the Caspian and Black Seas, and the waterways connecting...

 and Asia
Asia is the world's largest and most populous continent, located primarily in the eastern and northern hemispheres. It covers 8.7% of the Earth's total surface area and with approximately 3.879 billion people, it hosts 60% of the world's current human population...

. It is a member of the family Ranidae, or "true frogs".


The family the moor frog belongs to, Ranidae, is a broad group containing 605 species. The family is like a “catch-all” for ranoid frogs that do not belong to any other families. Since this is the case, the characteristics that define them are more general and the frogs are found all throughout the world, on every continent but Antarctica.

The moor frog’s genus, Rana
Rana (genus)
Rana is a genus of frogs. Species include such archetypal pond frogs as the common frog of Europe, brown frogs, and the New and Old World true frogs, including the various species of leopard frogs and the American bullfrog. Members of this genus are found through much of Eurasia, North America,...

, is a little more specific. Frogs of this genus are found in Europe, Asia, South America, and North America. The moor frog is not one of the ones belonging to either of the Americas, unlike the Foothill Yellow-legged Frog
Foothill Yellow-legged Frog
The Foothill Yellow-legged Frog is a small-sized frog from the Rana genus in the Ranidae family. This species can be found from northern Oregon, down California’s west coast, and into Baja California, Mexico. Both the Columbia Spotted Frog and the Cascades Frog, also part of the Rana genus, live...

, Cascades Frog
Cascades Frog
The Cascades Frog is a species of frog in the Ranidae family.It is found in western United States and possibly Canada, mainly in the Cascade Range and Olympic Mountains.-Description:-Appearance:...

, and Columbia Spotted Frog
Columbia Spotted Frog
The Columbia Spotted Frog, Rana luteiventris, is a North American species of frog. It is green to brown in color with spots on the dorsal surface. The belly and upper lip are white in color. Individuals can be distinguished from other Rana species by their shorter back legs, narrow snout and...

 which are all found in North America.

The moor frog’s scientific name, Rana arvalis means "frog of the fields". It is also called the altai brown frog because frogs from the Altai Mountains in Asia have been included in the Rana arvalis species. The altai frogs have some different characteristics like shorter shins, but currently there is no official distinction and all frogs are placed under Rana arvalis. The taxonomy may be more defined in the future.

Physical description

They are small frogs, 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 cm long but can reach up to 7 cm in length and their heads are more tapered than those of the European Common frog, (Rana temporaria). The skin on their flank and thigh is smooth and the posterior part of their tongue 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 pad
Nuptial pad
A nuptial pad is a secondary sex characteristic present on some mature male frogs and salamanders. Triggered by androgen hormones, this breeding gland appears as a spiked epithelial swelling on the forearm and prepollex that aids with grip, used primarily by males to grasp females during amplexus...

s on their first fingers and their paired guttural vocal sac
Vocal sac
The vocal sac is the flexible membrane of skin possessed by most male frogs. The purpose of the vocal sac is usually as an amplification of their mating or advertisement call...



The frogs can be found inhabiting an area stretching from the lowlands of Central and South Europe
Europe is, by convention, one of the world's seven continents. Comprising the westernmost peninsula of Eurasia, Europe is generally 'divided' from Asia to its east by the watershed divides of the Ural and Caucasus Mountains, the Ural River, the Caspian and Black Seas, and the waterways connecting...

 to Siberia
Siberia is an extensive region constituting almost all of Northern Asia. Comprising the central and eastern portion of the Russian Federation, it was part of the Soviet Union from its beginning, as its predecessor states, the Tsardom of Russia and the Russian Empire, conquered it during the 16th...

. The countries it lives in are: Austria, Belarus, Belgium, Czech Republic, Denmark, Estonia, Finland, France, Germany, Hungary, Italy, Latvia, Lithuania, Moldova, Netherlands, Norway, Poland, Romania, Russian Federation, Slovakia, Slovenia, Sweden, Switzerland, and Ukraine. However, it is believed that they are extinct in Switzerland and maybe Siberia as well. It is possible that the records of frogs being in Siberia at all were in error . Alsace
Alsace is the fifth-smallest of the 27 regions of France in land area , and the smallest in metropolitan France. It is also the seventh-most densely populated region in France and third most densely populated region in metropolitan France, with ca. 220 inhabitants per km²...

, France
The French Republic , The French Republic , The French Republic , (commonly known as France , is a unitary semi-presidential republic in Western Europe with several overseas territories and islands located on other continents and in the Indian, Pacific, and Atlantic oceans. Metropolitan France...

 constitutes the western boundary of their territory.

The types of land they can inhabit are greatly varied. They live in tundra
In physical geography, tundra is a biome where the tree growth is hindered by low temperatures and short growing seasons. The term tundra comes through Russian тундра from the Kildin Sami word tūndâr "uplands," "treeless mountain tract." There are three types of tundra: Arctic tundra, alpine...

, forest tundra, forest
A forest, also referred to as a wood or the woods, is an area with a high density of trees. As with cities, depending where you are in the world, what is considered a forest may vary significantly in size and have various classification according to how and what of the forest is composed...

, forest steppe
Forest steppe
A forest steppe is a temperate-climate ecotone and habitat type composed of grassland interspersed with areas of woodland or forest.-Locations:...

, and steppe
In physical geography, steppe is an ecoregion, in the montane grasslands and shrublands and temperate grasslands, savannas, and shrublands biomes, characterized by grassland plains without trees apart from those near rivers and lakes...

, forest edges and glades
Glade (geography)
A glade or clearing is an open area within a woodland. Glades are often grassy meadows under the canopy of deciduous trees such as red alder or quaking aspen in western North America. They also represent openings in forests where local conditions such as avalanches, poor soils, or fire damage have...

, semi-desert, swamps, meadows, fields, bush lands, 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 will hibernate somewhere between September and June, depending on the latitude of the location. Frogs in southwestern, plain 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 they have a song that sounds similar to that of the Agile Frog
Agile Frog
The Agile Frog is a frog in the genus Rana in the family of the true frogs.-Physical description:This species are skinny and have long limbs and a pointy snout. Adult males are rarely larger than 6.5 centimeters, while females can get up to 8 centimeters. Its ventral surface is light brown,...

, (Rana dalmatina). The call they make 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 3 to 28 days. The spawn of each frog is laid in one or two clusters of 500-3000 eggs
Egg (biology)
An egg is an organic vessel in which an embryo first begins to develop. In most birds, reptiles, insects, molluscs, fish, and monotremes, an egg is the zygote, resulting from fertilization of the ovum, which is expelled from the body and permitted to develop outside the body until the developing...

 in warm, shallow waters like in ponds.


Metamorphosis happens between June and October. Larvae are about 45 mm long and colored dark with small metallic dots. When they become tadpoles they will eat algae and small invertebrates. The adult frogs' feeding is halted during the breeding season, but their diet consists of insects and various invertebrates.


When moor frogs are on land and sense a threat they will make a large jump and bury themselves in soil or grass.

Population threats

It faces few major threats and is on the IUCN's Lowest Concern list. There are problems though with destruction and pollution of its habitat and breeding grounds through urbanization
Urbanization, urbanisation or urban drift is the physical growth of urban areas as a result of global change. The United Nations projected that half of the world's population would live in urban areas at the end of 2008....

, etc. where people overwhelm their environment. Droughts and predation can also cause problems but overall it quite adaptable and its population trend is considered stable.

Scientific studies

Extensive scientific experiments have been performed on the moor frog in an attempt to understand them better. This species is known to have a limited decline in population , but increased acidity levels in breeding areas might be a problem. Studies have shown though that when moor frogs are exposed to acidity they are able to adapt to it and their populations survive .

External links

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