Agile frog, Rana dalmatina Fitzinger in Bonaparte, 1838
History and origin
The Agile frog was first described by Fitzinger in Bonaparte in 1838, the scientific name of this species is Rana dalmatina. Rana is Latin and means frog. dalmatina is also Latin and means 'Dalmatian' from the Dalmatia region in western Balkans..
Characteristics
This species is characterised by their very long hind limbs.
Description =Size=
- Eggs: The eggs measure about 1.5 to 2.1 mm in diameter, they are laid in separate balls that measure about 9 to 12 mm in diameter.
- Tadpoles: The tadpoles measure 8 to 10 mm long when they exit the egg. Maximum sized tadpoles measure about 60 mm long.
- Juveniles: The juveniles measure 12 to 20 mm long when they exit the water.
- Adults: Males grow up to 60 to 65 mm long, females reach a size of up to 90 mm long, however they are on average 80 mm long.
=Morphology=
- Eggs: The eggs are laid in individual balls in 2 or 3 clusters of up to 1800 eggs.
- Tadpoles: They have a quite tall tail that doesn't come onto the back. The tail ends in a rounded blunt manor, contrary to R.arvalis and R.tempoaria.
- Adults: A svelte frog with a long pointy snout, very long hind limbs. They have no paratoid glands, very discrete dorsolateral folds. Their skin is smooth. The hind feet webbing is average. Their pupils are horizontal, they do not have a vocal sac.
=Patterns & colours=
- Eggs: They are brown, blackish on the upper side, and have a white blotch on the underside.
- Tadpoles: The upper body is brownish, the belly is light in colour.
- Adults: They are usually light brown, sometimes even slightly orange / red. Their dorsolateral folds are usually darker in colour. They usually have a series of dark markings on the back in form of small blotches. They have the bandit-like mask across the eyes from the nose towards the ears. Their hind legs are often barred with dark brown / black depending on the overall colouring of the specimen. Their eyes are golden or silvery. They belly is white.
Geographical range Found over most of France except the Mediterranean region, a small area in northern Spain, found over most of Italy, Greece and then their range becomes scattered and isolated in Germany over the rest of the Balkans and eastern Austria as well as Czech Republic. There is a small Danish population where they can also be found on offshore islands and a very small area of southern Sweden.
Subspecies
None described.
Sexual differences
Females ar generally larger, however males front legs are much more robust. Males have during the breeding season nuptial pads (greyish in colouring) on their thumbs.
Seasonal variations
Only the nuptial pads on the males varies from season to season.
Diet
They feed on a large proportion of insects such as wasps, earwigs and other... spiders and even slugs and snails.
Defensive habits
At first they try to escape danger by jumping away but if touched, they often flatten themselves onto the ground and raise their limbs, covering their eyes with their front legs. They may also emit a distress call.
Reproduction
The breeding season can last up to 1 to 2 months (starts as early as February). Reproduction sites are still water holes, in ponds, lakes or in swamps...The female finds a still, quite deep water hole. When the male finds the female he holds onto her under her front legs and has his hands on her chest, the male is now "glued" to the females back. The female then feels the time has come to push her eggs out so she moves over to a vegetated area in the water, ejects all of her eggs at one time which will glue to each other and sometimes be as large as a persons head. As the eggs come out of the female the male fertilizes them. The couple separate just after the expulsion of the eggs.
Sexual maturity, life span
The average life span for Rana dalmatina is about 10 years, they reach their sexual maturity in their third year.
Habits
Young specimens stay in the shallow water, where as the adults may be seem in the deep water. They hibernate deep underground at the edges of forests, and may even hibernate underwater such is the case in Greece.
Call
A fast, smooth series of croaks sounding like 'wug...wug...wug...' that may last for up to 10 seconds with about 4 to 6 impulsions per second, sound (p)www.oreilleverte.com:
Habitat
Found usually under 1000 m in altitude. They live in all kinds of forests depending on geographical area. They migrate to wetter areas to breed, sometimes even breeding in what seems to be poor quality forest ponds and streams. They hibernate deep underground at the edges of the forests and even underwater (Greece).
Predators
Birds are a great danger, the owl being the most dangerous.
Found over most of France except the Mediterranean region, a small area in northern Spain, found over most of Italy, Greece and then their range becomes scattered and isolated in Germany over the rest of the Balkans and eastern Austria as well as Czech Republic. There is a small Danish population where they can also be found on offshore islands and a very small area of southern Sweden.
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Agile frog, Rana dalmatina - © Konrad Mebert .jpg)
