The St. Bernard Dog is a very large breed of dog, a working dog from the Swiss Alps, originally bred for rescue. The breed has become famous through tales of alpine rescues, as well as for its enormous size.
The St. Bernard is a very large dog with a large head. The largest recorded Saint Bernard was over 6 ft in length and weighed 310 pounds, although the average weight of the breed is between 140 and 220 lb (64–100 kg) or more and the approximate height at the withers is 27½ inches to 35½ inches (70 to 90 cm). The coat can be either smooth or rough, with the smooth coat close and flat. The rough coat is dense but flat, and more profuse around the neck and legs. The coat is typically a red colour with white, or sometimes a mahogany brindle with white. Black shading is usually found on the face and ears. The tail is long and heavy, hanging low with the end turned up slightly. The dark eyes should have naturally tight lids, with "haws only slightly visible".
St. Bernards, like all very large dogs, must be well socialized with people and other dogs while young if they are to be safely kept as a pet. A St. Bernard not properly introduced to and socialized with children from a young age may pose a threat, not having learned to distinguish between a child and other, smaller animals. Nonetheless, in general St. Bernards are friendly.
Due to its large adult size, it is essential that proper training and socialization begin while the St. Bernard is still a puppy, so as to avoid the difficulties that normally accompany training large animals. An unruly St. Bernard may present problems for even a strong adult, so control needs to be asserted from the beginning of the dog's training. While generally not as aggressive as dogs bred for protection, a St. Bernard may bark at strangers, and their size makes them good deterrents against possible intruders.
The very fast growth rate and the weight of a St. Bernard can lead to very serious deterioration of the bones if the dog does not get proper food and exercise. Many dogs are affected by hip dysplasia or elbow dysplasia. Osteosarcoma (bone cancer) has been shown to be hereditary in the breed.
St. Bernards are susceptible to eye disorders called entropion and ectropion, in which the eyelid turns in or out. The breed standard indicates that this is a major fault.
The breed is also susceptible to epilepsy and seizures, a heart disease called dilated cardiomyopathy, and eczema.
Due to the likelihood of health problems in later years, the average lifespan for a Saint Bernard is around 8 years. In fact Agria a pet insurance from Sweden does not give life insurance for a Saint Bernard when he/she is above 8 years. Saint Bernads may live beyond 10 years but those dogs are rare.