The marsh frog (''Pelophylax ridibundus'') is a species of water frog native to

Europe Europe is a continent located entirely in the Northern Hemisphere and mostly in the Eastern Hemisphere. It is bordered by the Arctic Ocean to the north, the Atlantic Ocean to the west, the Mediterranean Sea to the south, and Asia to the east ...

and parts of western

Asia Asia ( , ) is the largest continent in the world by both land area and population. It covers an area of more than 44 million square kilometres, about 30% of Earth's total land area and 8% of Earth's total surface area. The continent, which ...

Description

The marsh frog is the largest type of frog in most of its range, with males growing to a size around 100 mm (3.9 in) SVL and females slightly larger (4 in) SVL. There is a large variation in colour and pattern, ranging from dark green to brown or grey, sometimes with some lighter green lines; a lighter line on the back is generally present. The frog will usually be darker coloured in early spring to absorb heat more efficiently. Tadpoles can reach up to 190 mm (7.3 in) in length, but this usually occurs in places with long winters where the tadpole has time to grow. File:Pelophylax ridibundus3.JPG,

Tadpole A tadpole or polliwog (also spelled pollywog) is the Larva, larval stage in the biological life cycle of an amphibian. Most tadpoles are fully Aquatic animal, aquatic, though some species of amphibians have tadpoles that are terrestrial animal, ...

File:PelophylaxRidibundusSpottedAdult.JPG, Female File:Marsh Frog imported from iNaturalist photo 400377577 on 3 December 2024 (cropped).jpg, Showing vocal sac.

Distribution and habitat

They occur in a large part of Europe starting from western

France France, officially the French Republic, is a country located primarily in Western Europe. Overseas France, Its overseas regions and territories include French Guiana in South America, Saint Pierre and Miquelon in the Atlantic Ocean#North Atlan ...

and spreading out into the

Middle East The Middle East (term originally coined in English language) is a geopolitical region encompassing the Arabian Peninsula, the Levant, Turkey, Egypt, Iran, and Iraq. The term came into widespread usage by the United Kingdom and western Eur ...

and about a quarter into

Russia Russia, or the Russian Federation, is a country spanning Eastern Europe and North Asia. It is the list of countries and dependencies by area, largest country in the world, and extends across Time in Russia, eleven time zones, sharing Borders ...

. There are also isolated populations in

Saudi Arabia Saudi Arabia, officially the Kingdom of Saudi Arabia (KSA), is a country in West Asia. Located in the centre of the Middle East, it covers the bulk of the Arabian Peninsula and has a land area of about , making it the List of Asian countries ...

and the

Russian Far East The Russian Far East ( rus, Дальний Восток России, p=ˈdalʲnʲɪj vɐˈstok rɐˈsʲiɪ) is a region in North Asia. It is the easternmost part of Russia and the Asia, Asian continent, and is coextensive with the Far Easte ...

, along with some introduced populations in the

United Kingdom The United Kingdom of Great Britain and Northern Ireland, commonly known as the United Kingdom (UK) or Britain, is a country in Northwestern Europe, off the coast of European mainland, the continental mainland. It comprises England, Scotlan ...

and other places. These frogs are very lenient in their habitats, and are able to inhabit a majority of different types of water bodies. Marsh frogs hibernate during the winter either underwater or in burrows, and are able to use the

magnetic field A magnetic field (sometimes called B-field) is a physical field that describes the magnetic influence on moving electric charges, electric currents, and magnetic materials. A moving charge in a magnetic field experiences a force perpendicular ...

of the

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to locate breeding ponds.

Diet

Adult marsh frogs have a large head that is able to devour a wide variety of prey, mostly arthropods and other invertebrates, as well as small fish, other amphibians (including conspecifics), reptiles, small birds, and rodents. In an analysis of 53 adults in

Thrace Thrace (, ; ; ; ) is a geographical and historical region in Southeast Europe roughly corresponding to the province of Thrace in the Roman Empire. Bounded by the Balkan Mountains to the north, the Aegean Sea to the south, and the Black Se ...

flies Flies are insects of the Order (biology), order Diptera, the name being derived from the Ancient Greek, Greek δι- ''di-'' "two", and πτερόν ''pteron'' "wing". Insects of this order use only a single pair of wings to fly, the hindwin ...

made up 40% and

beetles Beetles are insects that form the Taxonomic rank, order Coleoptera (), in the superorder Holometabola. Their front pair of wings are hardened into wing-cases, elytra, distinguishing them from most other insects. The Coleoptera, with about 40 ...

20% of their diet. These frogs have been found to climb onto

water buffalo The water buffalo (''Bubalus bubalis''), also called domestic water buffalo, Asian water buffalo and Asiatic water buffalo, is a large bovid originating in the Indian subcontinent and Southeast Asia. Today, it is also kept in Italy, the Balkans ...

so they could eat the flies attracted to it, hinting at a possible mutualistic relationship. As tadpoles, they eat a wide range of organic matter including

algae Algae ( , ; : alga ) is an informal term for any organisms of a large and diverse group of photosynthesis, photosynthetic organisms that are not plants, and includes species from multiple distinct clades. Such organisms range from unicellular ...

detritus In biology, detritus ( or ) is organic matter made up of the decomposition, decomposing remains of organisms and plants, and also of feces. Detritus usually hosts communities of microorganisms that colonize and decomposition, decompose (Reminera ...

, decaying plants, invertebrates, and dead animals.

Hybridogenesis

There are known three hybridogenetic hybrids of the marsh frog: * edible frog ''Pelophylax'' kl. ''esculentus'' (usually genotype RL):
pool frog ''P. lessonae'' (LL) × ''P. ridibundus'' (RR) * Graf's hybrid frog ''Pelophylax'' kl. ''grafi'' (PR):
Perez's frog ''P. perezi'' (PP) × ''P. ridibundus'' (RR) or
Perez's frog ''P. perezi'' (PP) × edible frog ''P.'' kl. ''esculentus'' (RE)
(it is unclear which one crossing was the primary hybridization) * Italian edible frog ''Pelophylax'' kl. ''hispanicus'' (RB):
Italian pool frog ''P. bergeri'' (BB) × ''P. ridibundus'' (RR) Their populations are maintained however through other crossings by hybridogenesis. In places where they were introduced, marsh frogs may pose a threat to the native '' Pelophylax'' by diluting the gene pool, but there is evidence that although they may hybridize they do not affect the overall population that greatly.

References

External links

* * Listen t
''Pelophylax ridibundus'' call sound
{{Authority control Pelophylax Amphibians of Afghanistan Amphibians of Armenia Amphibians of Iran Amphibians of the Middle East Vertebrates of the Arabian Peninsula Amphibians of Europe Amphibians described in 1771 Taxa named by Peter Simon Pallas Habitats Directive species