Several generations of the dog species have lived and died since the catastrophe. Each was more affected by the Zone than the previous one. Rapid mutation lead to a vast improvement in previously peripheral abilities, frequently at the expense of primary ones. The most notable biological change was the loss of sight, paired with an uncanny development of smell. As it turned out, blind cubs survived in the Zone as well as normal ones, if not better. As a result, the common dog quickly became extinct in the Zone, giving way to a new breed - that of blind dogs. The animals instinctively identify and avoid anomalies, radiation, and other invisible dangers that plague the Zone. Like their wild ancestors - the wolves - blind dogs hunt in packs. An encounter with a large group of these animals can be dangerous even to an experienced and well-armed stalker.
Personal Notes
Blind Dogs are pretty weak but during the beginning stages of the game a pack of Blind Dogs can still be very dangerous - I've even seen experienced stalkers fall prey to packs, in spite of them carrying powerful weapons.
Locations
Blind Dogs can be found in almost any area of the Zone but they tend to be dominant in Cordon, Garbage, Agroprom Research Institute, Dark Valley, Wild Territory, Army Warehouses, Pripyat and outside the control point at the Bar.