In Slovenia, four species of brown frogs (subgenus Rana) live, and in Notranjski Park two of these. One of them is rosnica (Rana dalmatina). Rosnica, which we also call sivka, is a medium-sized frog. The body length of an adult animal ranges from 6 to 9 cm, and males are usually somewhat smaller than females. Rosnica is characterized by extremely long hind legs, which allow the largest individuals to jump over more than one meter. The dorsal side of this frog is uniformly brown and it also has no dark spots or blotches on the sides. Like other brown frogs, rosnica also bears a distinctly dark brown mask over the eyes, and on the hind legs it has a darker pattern of broad transverse bands. The entire ventral side is a uniform white, without darker spots or specks along the middle. Males have white throats, and females pale orange or yellowish throats. Rosnica has an elongated and somewhat pointed snout, so from a bird's-eye view its head looks pointed. The tympanum, a rounded cavity behind the eye, is in this species almost as large as the eye.
It is widespread throughout Slovenia. It occurs up to 1000 m above sea level, but is more common in lower regions. Most of its adult life is spent on land. It prefers warmer habitats, where in light deciduous forests, along forest edges, in forest clearings and in marshy meadows it searches for food. With its color and shape, rosnica easily blends with the dry leaves in the surroundings and, if it remains motionless, it is hard to notice. This is a diurnal animal that hunts insects and similarly sized invertebrates especially on rainy days and on damp days that follow.
Males of brown frogs do not have external vocal sacs typical of representatives of the green frog group, and rosnica is no exception. Rosnica breeds in deeper, at least 1 dm deep, standing or slowly flowing waters. Males call at breeding sites underwater and they are not easy to hear. Females are more responsive to their calls and early in spring, from February to April, readily respond to the male's rhythmic kro-kro-kro-kro-kro. A female attaches a single spherical clutch to a branch or stem of an aquatic plant, which contains from 300 to 1500 eggs and has a diameter of about 10 cm. The spawn gradually detaches from the attachment site and spreads across the surface of the water. In summer rosnice retreat from the water bodies where they spawned to land and can travel even several kilometers away. They overwinter on land.
Rosnica is protected in Slovenia and, in addition, as a vulnerable (V) species is listed on the Red List of endangered amphibians of Slovenia!
