History and origin
The Common Tree frog was first described by Linnaeus in 1758, the scientific name of this species is Hyla arborea. Hyla from Greek meaning 'to bark', this names is given because of this frogs bark-like call. Arborea is from Latin and means 'tree', 'of the trees', this species is very arboreal.
Characteristics
This species is characterised by the continued dark line on the flanks.
Description =Size=
- Eggs: The eggs are about 1.5 to 2 mm in diameter, laid in individual balls of about 4 mm in diameter.
- Tadpoles: The tadpoles measure 3 to 5 mm long when they hatch, growing up to 50 mm long.
- Juveniles: The juveniles measure 12 to 20 mm long when they exit the water.
- Adults: Adults measure up to 50 mm long max. (averaging between 30 to 40 mm long). =Morphology=
- Eggs: The eggs are laid individual balls that are laid in small groups of about 50 (= 1 mass).
- Tadpoles: They have a large, very tall tail coming onto the back and rounded on the end. Their eyes are on the sides.
- Adults: They are an elegant, slim frog with very long and thin hind legs, their skin is very smooth. Their snout is rounded, they do not have paratoid glands, their pupils are horizontal. The hind feet webbing is average, They have no dorsolateral folds. =Patterns & colours=
- Eggs: They are small yellowish, creamy rounded eggs encased inside an individual transparent ball.
- Tadpole: Their general colouring is olive brown, uniform.
- Adult: They are usually bright green with a black line bordered with white running from their nose down towards their hind legs passing through the flanks, this line usually comes up onto the back at the hind legs. Sometimes there may be small blotches placed irregularly along the back, they are darker then the background colour. Sometimes specimens may be greyish brown with or without these darker blotches. The males vocal sac is usually yellowish. Their eyes are golden yellowish, and their belly is whitish.
Geographical range They are found all over Europe except the United Kingdom, Ireland, Finland, Norway, absent from western Mediterranean islands (Corsica, Sardinia, Balearics).
Subspecies - arborea - Found over most of the range. - kretensis - Found on Crete.
- molleri - Found in Spain and in south western France.
Sexual differences
Females are larger. Males have a vocal sac which is visible when not in use thanks to its yellowish colour.
Seasonal variations
At the beginning of the year, specimens are darker due to their need to heat up faster.
Diet
They feed on spiders, earwigs, beetles and other small insects. Tadpoles feed mainly on plants in the water.
Defensive habits
When they are touched, they emit a mucus from their skin. They may also emit a distress call.
Reproduction
The breeding season can last up to 3 months between April and June, mating occurs at night. Reproduction sites are still water holes and are usually well vegetated areas of water like ponds, marshes and streams... The male jumps onto the females back and with his hands takes a grip around the front end of her belly just behind the front legs. With his chin glued to the females neck (back of the neck). When the female moves the male lifts his legs up and hangs on for a ride. The male gently squeezes the female and when the eggs start to be laid the male fertilizes them. Then the male carefully wraps them on roots or wood, branches or even a stem of grass all in the water.
Sexual maturity, life span
The average life span for Hyla arborea is about 15 years, they reach their sexual maturity at the end of their first year for males and in their second year for females.
Habits
Active in early evening and night. Often seen by day exposed in the sun as they sleep. They are the most arboreal of the 3 Hyla species of France. The newly metamorphosed frogs usually move away from their birth pool, in a few weeks they will be a few hundred meters from it.
Call
A sharp, fast call 'epp...epp...epp...' called on average four to six times a second. sound (p)www.oreilleverte.com:
Habitat
They are found usually under the altitude of 600 m, they enjoy areas with lots of sun and an annual temperature of above 12 degrees centigrade. They live in gardens, near streams, canals, at the edges of cultivated land and sometimes in villages. They breed mainly in flooded fields such as cultivated fields, but also in ponds. They are found sometimes near artificial waterways.
Predators
Their main predators are birds, but also large Pelobates fuscus tadpoles are predators for the tadpoles.
They are found all over Europe except the United Kingdom, Ireland, Finland, Norway, absent from western Mediterranean islands (Corsica, Sardinia, Balearics). 
