Size and Build
Jack Russell Terriers are a small breed, typically standing between 25 and 30 cm at the withers for both males and females, and weighing between 6.4 and 8.2 kg. Despite their size, they have a sturdy, muscular build with compact bodies that express strength and agility. They feature a level back with a slight loin dip, deep chests with oval ribcages, and well-muscled hindquarters, supporting their dynamic movement and endurance.
Coat and Colours
The breed can have either a smooth or rough coat, both with softer undercoats that offer weather protection. The predominant base colour is white with distinctive black and/or tan markings, as specified in the Kennel Club standard. Acceptable coat patterns include white with black markings, white with black and tan markings, and white with tan markings. Seasonal shedding occurs, more pronounced during spring and autumn, requiring regular brushing to maintain coat health.
Distinctive Features
Characteristic to the breed is a flat and moderately wide skull narrowing towards the eyes, which themselves are small, almond-shaped, dark, and expressive with a keen, alert look. Jack Russells have black noses and tight black lips, with ears that may be button or dropped, carried close to the head. The tail is set high, thick at the base, carried upright when alert, and relaxed when resting. Their gait is free-moving and straight, demonstrating efficiency and drive without exaggeration.
Gender Differences
Males tend to be marginally larger and more muscular, though size overlap is common due to breed standards that allow some variation. Temperamentally, males and females share similar traits, though individual personality differences may occur. Both genders require equal mental and physical stimulation.