According to the Sclater classification of zoogreographical areas on Earth, Croatia is situated in the old-northern area - Palearktis of the northern subworld - Holarktis in the northern world- Arctogaea.
Due to its geographical position, Croatia is situated in two subareas of old-northern area: in the European and the Mediterranean.
In accordance to that fact, in the Pleistocen period Croatia was only partly under ice and was thus a shelter and a place of refuge for many species.
Owing to that fact, Croatia has a heterogeneous fauna in which you can
find:
- pre-ice forms (the Tertiary period)
- north-european imigrants (the Pleistocen period)
- post-ice european fauna
- mediterranean species
- north-african species
A further division of Croatia into belts, zones and parts made Hadzi in
1925.