3. German Shepherd
A breed of dogs that originated from Germany, the German Shepherd can weigh as much as 70 to 100 lbs. Known for being intelligent, confident, alert, vigilant, and fearless; the police use them for their K-9 units. However, caution must be exercised with Shepherds as they can become overprotective of their family and territory, and if not socialized correctly; can lead to attacks.