Agile frog

Agile frog
Conservation status
Least Concern  (IUCN 3.1)[1]
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Class:	Amphibia
Order:	Anura
Family:	Ranidae
Genus:	Rana
Species:	R. dalmatina
Binomial name
Rana dalmatina Fitzinger in Bonaparte, 1839
Distribution (green)
Synonyms
Rana agilis Thomas, 1855 Rana gracilis Fatio, 1862 Rana temporaria var. agilis Schreiber, 1875 Rana temporaria agilis Bedriaga, 1881 Rana agilis agilis Cope, 1886 Rana (Crotaphitis) agilis Schultze, 1891 Rana (Rana) dalmatina Guibé, 1950 Rana agiloides Brunner, 1951 Rana mülleri Brunner, 1959 Rana (Rana) dalmatina Dubois, 1987 Rana (Laurasiarana) dalmatina Hillis & Wilcox, 2005

The agile frog (Rana dalmatina) is a European frog in the genus Rana of the true frog family, Ranidae.^[2]

This species is fat and has long limbs and a pointy snout. Adult males are rarely larger than 6.5 cm, while females can grow up to 8 cm. Its dorsal surface is light brown, reddish-brown, or light greyish-brown with very little contrast. Triangle-shaped spots reach from the temple to the eardrum, which are dark brown. The underside of the agile frog is white without any spots. During mating season, the males often become dark brown.^[3]

The hind legs are unusually long, which allow this species to jump further than other similar frogs - they have been known to jump up to two metres in distance. The pupils are horizontal. The colour of the upper third of the iris (above the pupil) is lighter and gold in coloration. The tympanum is about the size of the diameter of the eye. The gland stripes on the frog's back are not very developed and partially interrupted.

The call is a fairly quiet "rog ... rog ... rog", and can last for up to 12 seconds, and almost sounds like a clucking chicken. They often also call under water, so the calls can only be heard from a very short distance by observers. Spawning only lasts a few days, and during this period, the males sometimes gather in large calling groups on the water surface to attract females. In Central Europe, spawning usually occurs in the first 20 days of March, but can also be delayed, depending on the weather. The spawn clumps consist of 450 to 1800 eggs, and are usually attached to tree branches, roots, or plant stems at depths of 5–40 cm (2–16 in). Therefore, they rarely sink to the bottom. Unlike the moor frog (Rana arvalis) and common frog (Rana temporaria), the agile frog does not lay its spawn all in one clump. The diameter of a single egg, not counting the gelatinous shell, is 1.5–2.1 mm (0.06–0.08 in).^[3]

Adults of agile frog eat arthropods like caterpillars, spiders, millipedes, flies, beetles, cicadas and collembolans.^[4][5][6][7] Tadpoles eat plant material.^[8]

The agile frog prefers light deciduous mixed forests with plentiful water. The open land around a forest is often also populated, as long as it is connected to the forest by shrubs. In dry, warm forests, this species often also lives far away from the water. Of the three Middle European Rana species, this frog likes warmth and dryness the most.^[1]

The agile frog can be found in France, the Channel Islands, parts of Germany, Denmark, Sweden, Italy, the Czech Republic, Slovakia, Austria, Hungary, on the Balkans, Greece, and by the Black Sea. The species once lived in the Great Britain, during middle Saxon times, with archaeological remains recovered in East Anglia.^[9][10] Celtic Reptile & Amphibian have discussed reintroducing the species.^[11][12] It has undergone a reintroduction on Jersey, by Durrell Wildlife Conservation Trust, as it was very close to extirpation on the island.^[13][14]

• Media related to Rana dalmatina at Wikimedia Commons