2. Lhasa Apso

The Lhasa Apso boasts a storied history that makes it one of the most effective small dogs for security. Bred in the Himalayan mountains of Tibet, these dogs served as internal sentinels inside Buddhist monasteries—earning them the native name Abso Seng Kye, or “Bark Lion Sentinel Dog.” While giant Tibetan Mastiffs guarded the outer gates, Lhasa Apsos patrolled the inner hallways.

Weighing 12 to 18 pounds, Lhasa Apsos possess exceptionally acute hearing. They can distinguish between the footsteps of familiar family members and strangers long before anyone reaches the door. They remain calm and composed until they sense something unusual, at which point they raise a sharp, persistent alarm.