Bernese Mountain Dog
Bernese Mountain Dog facts: a 10-year life expectancy, high cancer risks, and the specific history of this Swiss farm dog.
8 to 10 years of life expectancy, with cancer accounting for roughly 55% of all deaths. This low number persists even when compared to other large breeds, driven by a high prevalence of specific genetic disorders and a unique susceptibility to malignant histiocytosis.
The Bernese Mountain Dog, or Berner Sennenhund, is a large, heavy dog originating from the canton of Bern in Switzerland. It is one of four Sennenhund-type breeds with ancestral roots in Roman mastiffs, historically used as an all-purpose farm dog to guard property, drive cattle to alpine pastures, and pull carts of milk and cheese. The name "Sennenhund" literally translates to "dog of the Senn," referring to the alpine herders and dairymen they accompanied. While the breed was formally recognized in 1912, it was not until 1937 that the American Kennel Club granted official recognition, and it now ranks 19th in popularity in the US.
Size and the distinctive tri-colour coat
The Bernese is a large, heavy dog with a distinctive tri-coloured coat, black with white chest and rust-coloured markings above the eyes, on the sides of the mouth, and on the front legs. It is the only Sennenhund breed with a long coat. The ideal markings include a white "Swiss cross" on the chest, a white horseshoe shape around the black nose, and a "Swiss kiss" behind the neck. The AKC breed standard disqualifies blue eyes and any ground colour other than black. Males typically stand 64–70 cm at the withers and weigh 35–55 kg, while females are slightly smaller at 58–66 cm and 35–45 kg.
Cancer and genetic health risks
Health issues are the defining characteristic of the breed, with a high frequency of neoplasia and a life expectancy significantly lower than other large breeds. One study found that 55% of Bernese deaths were attributable to cancer. The breed has a high risk of malignant histiocytosis, a rapidly progressive multisystem cancer that accounts for a quarter of all tumours in the breed and is linked to mutations in genes like CDKN2A/B and PTEN. Other common conditions include elbow dysplasia (affecting 13.91% to 26% of the breed), immune-mediated glomerulonephritis, and high-grade mastocytoma. The Bernese is also one of the more commonly affected breeds for type I von Willebrand's disease.
Temperament and working abilities
The Bernese is a calm, attentive, and impetuous breed that tends to attach to one person while maintaining an inherent suspicion of strangers. They are untiring and resistant to cold winters, making them excellent defenders of a home or stable. Historically, they were used for pulling small carts, a task they still enjoy with proper training, and they have been employed by the police in Switzerland. In 2010, the breed became eligible for AKC Herding Events, and while they are not prone to biting, they can be unruly if not properly socialized.
Why the lifespan is so short
Despite the general rule that larger breeds have shorter lives, the Bernese Mountain Dog's lifespan is exceptionally low even for its size. A 2016 Swiss study found an average life expectancy of 8.4 years, while a 2013 Dutch study found 8 years. A 2024 UK study reported a slightly higher average of 10.1 years, compared to 12.7 years for purebreds in general. A 2005 Swedish study found that 72% of Bernese Mountain Dogs died before reaching 10 years of age. This discrepancy is largely due to the breed's specific genetic vulnerabilities to cancer and renal disease, which strike with higher frequency and mortality rates than in other breeds.