A quiet, powerful guardian with a gentle family side.
Origin
England
Height
24–27 in (61–69 cm)
Weight
100–130 lb (45–59 kg)
Lifespan
7–9 years
Coat
Short, dense — low-maintenance
Energy
Moderate
Overview
The Bullmastiff is a massive, muscular guardian bred to be fast, silent, and fearless. Developed to catch poachers, it was designed to pin rather than harm intruders — a restraint that lives on in its steady, confident temperament.
Despite its imposing size, the Bullmastiff is affectionate, calm, and devoted to its family, often gentle with children. It is naturally protective and independent, needing early socialization and a confident, experienced owner.
History
Created in 19th-century England by crossing Bulldogs and Mastiffs, the Bullmastiff served gamekeepers by tracking and holding poachers on large estates. Its blend of power, courage, and control made it a formidable guardian.
Where it comes from
England
Highlighted in the Bullmastiff's lineage color on the map.
Temperament
The Bullmastiff is steady, loyal, and quietly watchful, forming strong family bonds while remaining wary of strangers. It is strong-willed and needs early socialization and consistent, firm, positive training given its size and drive.
Health to watch
Joint malformation is common in giant breeds; screening and lean weight help protect the joints.
The deep chest raises the risk of gastric torsion; smaller meals and rest around eating are wise.
The breed has elevated rates of certain cancers and heart conditions; regular checkups aid early detection.
General breed tendencies, not a diagnosis. Every dog is an individual — pair this with regular veterinary care.
Care essentials
Moderate daily activity keeps the Bullmastiff fit without overstressing growing or aging joints.
Early, broad exposure keeps its powerful guarding instincts balanced and reliable.
As a heavy, short-muzzled breed, it tolerates heat poorly; keep it cool and limit exertion when warm.
XPET builds each pet a digital twin — modeling their real biology instead of breed averages, so care stays personal.