Extremely loyal, this breed is eager to please its owners but due to its size, it is essential that proper training and socialization begin early in life while the dog is still a manageable size. An unruly St Bernard presents a problem for even a strong adult so control needs to be asserted from the beginning.
St Bernards will bark at strangers and their size makes them good deterrents against most intruders although their aggression as guard dogs rarely equals breeds designed for that