In dogs of native breeds (“Hmong,” “Phu Quoc,” and “Zang Soi”), the features of behavior pre-adapted to interaction with humans and formed in the process of directional selection have been revealed. Behavioral characteristics (contactiveness, activity, playfulness, reaction to the unexpected appearance of an unfamiliar object, and abrupt sounds) were used to evaluate the dogs’ suitability for training for use as service detector dogs. It was shown that native dogs even without directional selection can show high indices of activity and contact with a human, similar to those found by the authors earlier for European breeds. Indicators of playfulness and reaction to unfamiliar objects and sharp sounds are formed only in the process of directional selection. The “Zang Soi” dog recommended for breeding and use as detection dogs turned out to be the closest to the European breeds in terms of activity and contactiveness indices.