The intruder, when discovered, may attack the dog if the handler is not immediately at hand, or there could be an accomplice (or accomplices) who might attack the dog and his handler.
The dog must therefore be prepared to assess the situation and react in a manner which will minimize the possibility of injury to his handler and himself. At the same he should remain in contact with at least one intruder.
Courage together with the physique and ability to attack are now very prominent requirements. However, the ability to apply self-control on the termination of hostilities is equality important. A dog of very balanced character is a necessity under such conditions.
Keeping an intruder at bay
At attentive and preferable a barking dog which maintains contact will certainly make an intruder think twice about trying to make a quick exit. Although self-confidence is a very important characteristic, a dog with an impressive physique and stature will pose more of a real threat to an intruder than will a small one.
Preventing the escape of an intruder
An intruder is unlikely to try to escape when found by a large and powerful dog which has determination to maintain contact. However, the intruder may well size up the situation before the dog is close enough to detect his presence and may try to make a quick exit prior to discovery.