Mastiff
Also known as: English Mastiff, Old English Mastiff
One of the largest dog breeds by mass - a gentle, dignified English guardian that is calm, good-natured and deeply affectionate with its family. Quietly loyal and patient, the Mastiff combines a courageous heart with a steady, trustworthy temperament that makes it a remarkable companion.
Origin and purpose
The Mastiff is an ancient British type, used over millennia as a war dog, estate guardian and (less creditably) in blood sports, before being refined into the modern show breed in the 19th century. It was bred above all to be a massive, intimidating but steady guardian.
Temperament
Kennel authorities describe the Mastiff as dignified, good-natured, calm and courageous — devoted to its family and naturally protective without being aggressive when well-raised. It is sensitive and responds best to gentle, consistent training. Its size demands early manners training while it is still liftable. Individual temperament varies more than the breed label suggests (Morrill et al., Science 2022).
Health and longevity
As a giant breed the Mastiff is typically short-lived. Controlled growth, lean weight and breeders who health-test are essential.
Common health conditions
Living with a Mastiff in Ottawa
This section is specific to Ottawa (Canadian Food Inspection Agency (CFIA)). The rest of this guide applies to the breed anywhere.
Toronto Animal Services
Dogs in Toronto must be licensed annually with Toronto Animal Services. There is no provincial housing breed restriction on licensing, but Ontario's Dog Owners' Liability Act (DOLA) bans pit bull-type dogs from the province — this applies citywide regardless of housing type.
Toronto Humane Society / Toronto Animal Services: Not eligible
This breed is not eligible for Toronto Humane Society / Toronto Animal Services.
Licensing
Toronto dog licence required annually from Toronto Animal Services: CAD $32/year (sterilised) or CAD $78/year (unsterilised); microchipping strongly encouraged. Source: Toronto Animal Services (toronto.ca/community-people/animals-and-pets/pets-in-the-city/dogs/).
Climate & exercise in Ottawa
Ottawa is humid continental; cold winters (Jan avg -5°C, windchill to -20°C); warm humid summers (Jul avg 27°C); road salt season November through March. walk before 8am or after 7pm in July and August; pave test before midday walks — Toronto pavement can exceed 55°C in direct summer sun. Toronto's humid summer heat raises risk for brachycephalic breeds (French Bulldog, Pug, Bulldog) in July–August; road salt and ice-melt chemicals on sidewalks November–March require paw-washing after every winter walk; the Rouge Valley and Don Valley ravines are prime Ixodes scapularis tick habitat.
Parasite prevention
Plan for Lyme disease tick (Ixodes scapularis, blacklegged tick) present in Toronto ravines and Rouge National Urban Park — prevention April through November; heartworm prevention June through November (Ontario mosquito season); road salt paw protection November through March.
Cost of ownership in Ottawa
Local Mastiff cost figures for Ottawa are being verified. Budget for purchase or adoption, initial setup, food, grooming, routine veterinary care, parasite prevention and pet insurance. Figures are quoted in $.
Health & longevity
Responsible breeders health-test their breeding dogs. Ask to see current certificates before committing.
Nutrition note: Giant-breed controlled-growth puppy diet and lean adult weight protect joints; multiple smaller meals reduce bloat risk.
Known breed conditions
DNA & screening panel
Cost of ownership
FLAG: indicative Singapore estimate — very high food/medication doses by weight; short lifespan limits total years.
Registries
Sources & references
- AKC — Mastiff breed standard & traits[Breed standard / registry]
- The Kennel Club (UK) — Mastiff[Breed standard / registry]
- Merck Veterinary Manual — hereditary and breed-associated disease[Veterinary reference]
- Orthopedic Foundation for Animals (OFA) — breed health screening / CHIC testing[Peer-reviewed / VetCompass / OFA]
- NParks/AVS — Pets in HDB flats (approved small breeds; ≤55 cm shoulder height)[Breed standard / registry] · checked June 2026
- Morrill et al., "Ancestry-inclusive dog genomics…", Science 376 (2022) — breed ≈ 9% of behaviour[Peer-reviewed / VetCompass / OFA] · 2022
Source tiers: 1 = breed standard / registry authority; 2 = peer-reviewed / VetCompass / OFA; 3 = veterinary reference; 4 = encyclopaedic. PawHub cites only tiers 1–4 and never blogs or e-commerce pages. Behavioural traits carry low confidence — breed explains ~9% of individual behaviour variation (Morrill et al., Science 2022).
Image credits
- Image 1: Pleple2000 · CC BY-SA 3.0 · via Wikimedia Commons
- Image 2: Radovan Rohovsky · CC BY-SA 3.0 · via Wikimedia Commons
- Image 3: Wikimedia Commons contributor (Blikly) · Public domain · via Wikimedia Commons
