The Strandja region together with the coastal line is one of the richest in animal species in
The animal diversity and identity is very well preserved for the reason that for a number of decades the access to the mountain has been restricted in view of the proximity of the state border.
The Strandja mountain abounds in birds. There are certain times of the year when the number of birds reaches 261, which represents 68% of all the birds found in
A considerable portion of this number are migrating birds for one of the major European bird migration routes - VIA PONTICA (the Black Sea Route) passes over the Strandja mountain. 17 of the bird species are listed in the Red Book of Bulgaria and 1 is listed in the World Red Book There are 54 mammal species such as wolves (population 20-25), wild boars (460), deer (660), jackals (2000), wild cats, rabbits.
The otter population in the
is the best preserved in
. 6 species are listed in the Bulgaria Red Book and 1 (the monk-seal) in the World Red Book. The actual number of animal species is probably higher than 54, for the caves of the Strandja are only partially explored.