Marsh frog

(Pelophylax ridibundus)


Facts

Marsh frog IUCN LEAST CONCERN (LC)

 

Facts about this animal

Marsh Frogs are the largest frogs in Europe (up to 17 cm). There is a large variation in colour and pattern, ranging from dark green to brown or grey. Large dark dorsal spots vary considerably in size, number and arrangement. Light middorsal line often present. No temporal spot. Belly greyish-white or greyish-yellow with dark spotted or blotched-like pattern, sometimes without this pattern.

 

Hibernation occurs from September-October (in northern regions) or November-December (in the south) to the beginning of June or January-February, respectively. In southern regions, the hibernation is frequently interrupted by warm weather. In unfrozen water bodies (in particular in the southern parts of its distribution), the frog may even remain active throughout the winter. As a rule, hibernation occurs in water, but in some locations it occurs in rodent burrows and holes in river banks and lake shores. Group hibernation is typical, but the groups usually do not exceed several dozen individuals.

 

Breeding starts from several days to one month after the frogs' spring appearance. The males form loud choruses. The clutch contains up to 16.000 eggs. The time of metamorphosis depends on weather, peculiarities of habitat and latitude but usually falls into April-November. In some places of Europe and Asia regular hibernation of tadpoles (up to a few thousand individuals in one pond) has been recorded. Such tadpoles attain sometimes exceptionally large size (total length to 185 mm) and undergo metamorphosis in the next spring. Sexual maturity is attained in the 1st-4th year of life.

 

The diet of the Marsh Frog consists of dragonflies and other insects, spiders, earthworms and slugs, however Rana ridibunda is quite voracious and in fish ponds, it even eats small fishes and often eats conspecific and other amphibians, as well as reptiles and even small birds and rodents.

Did you know?
Concerning their reproduction the “waterfrogs” are indeed remarkable: While the Pool Frog (Rana lessonae) is a true species, the Edible Frog (Rana esculenta) is a hybrid between the Pool Frog and the Marsh Frog (Rana ridibunda). During the ice ages the population of the common ancestor of both species was split into two. The two species (R, lessonae and R. ridibunda) diverged, but remained genetically close enough to be able to create fertile hybrids. The genome of the Edible Frog (R. esculenta) therefore consists of two parts of each of its parent species. When eggs or sperms are produced, however, the whole genome-part of R. lessonae is destroyed (Hybridogenesis. Therefore egg- and sperm cells of R. esculenta contain only R. ridibunda genome. When, however, Edible Frogs (R. esculenta) mate with each other, their offspring generally die in an early tadpole stage, so there are no pure populations of Edible Frogs. The reason for this is that the R.ridibunda genome has been transferred – as we shall see below – from one generation to the next without recombination (clonal) and has lead to an accumulation of defective mutant genes. On the other hand, when R. esculenta mates with R. lessonae, the genome of R. lessonae is combined in the offspring again with R. ridibunda genome and the larvae develop again into Edible Frogs (R. esculenta). Thus, the Edible Frog can continue to exist in mixed populations together with the Pool Frog, without the presence of it other parent species, the Marsh Frog (R. ridibunda). For the Pool Frog (R. lessonae) this situation is however an evolutionary challenge: The offspring of pairings with the Edible Frog (R. esculenta) destroy the R. lessonae-part of the genome, instead transferring it to the next generation. Thus the Pool Frogs should avoid matings with the Edible Frogs, while the latter must mate with Pool Frogs in order to secure their existence. Obviously so far there have been enough cases where the frogs did not make the right choice and where specimens of one species mated with specimens of the other, thus securing a continuous common existence of both forms. If Marsh Frogs (R. ridibunda) enter the picture (e.g. in the southern part of Switzerland), then gradually the R. ridibunda genome “takes over” and both R. lessonae and R. esculenta are eventually replaced by R. ridibunda.


 

Factsheet
Class AMPHIBIA
Order ANURA
Suborder NEOBATRACHIA
Family RANIDAE
Name (Scientific) Pelophylax ridibundus
Name (English) Marsh frog
Name (French) Grenouille rieuse
Name (German) Seefrosch
Name (Spanish) Rana verde común
CITES Status Not listed
CMS Status Not listed

 

 

Photo Copyright by
Christian Fischer

Distribution

 


Distribution
Range Afghanistan, Albania, Armenia, Austria, Azerbaijan, Bahrain, Belarus, Bulgaria, China, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Georgia, Germany, Greece, Hungary, Iran, Islamic Republic of, Iraq, Israel, Italy, Kazakhstan, Kyrgyzstan, Latvia, Lithuania, Luxembourg, Moldova, Republic of, Morocco, Netherlands, Poland, Romania, Russian Federation, Saudi Arabia, Slovakia, Slovenia, Tajikistan, Turkey, Turkmenistan, Ukraine, Uzbekistan. Introduced in: Belgium, Spain, Switzerland, United Kingdom.
Habitat A highly opportunistic amphibian. It lives in mixed and deciduous forests, forest steppe, steppe, semidesert and desert zones. Being a semiaquatic species, the frog inhabits a wide variety of flowing and stagnant water habitats, from shallow puddles and ponds to large lakes and rivers, as well as mountain streams.
Wild population Rana ridibunda is generally an abundant amphibian. In the rivers of the southern part of Europe, its abundance may even reach more than a thousand individuals per kilometer of the bank. However, it is relatively rare in swift mountain streams.
Zoo population 92 reported to ISIS (2007)

In the Zoo

Marsh frog

 

How this animal should be transported

For air transport, Container Note 45 of the IATA Live Animals Regulations should be followed.

 

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