American Mastiff — breed guide
A modern American line bred from Mastiff and Anatolian stock specifically for a drier mouth — the drool is the selling point.
At a glance
- Group
- working
- Size
- Giant
- Weight
- 54–91 kg (119–201 lb)
- Life span
- 10–12 years
- Coat
- Short dense coat
Living with a American Mastiff
- Low energy — happy with gentle daily exercise.
- Light grooming — a brush now and then.
- Moderate shedding.
- Trainable with consistency.
- Quiet.
- Good with children.
- Usually fine with a familiar dog; strange dogs need managing.
- Typically lives happily with a cat.
- Not well suited to a flat — space, exercise need or voice works against it.
- Better with previous experience behind you.
- Sensitive to heat; keep summer walks short.
- Handles cold well.
- Flat-faced (brachycephalic): breathing is harder in heat and under exertion, so walk weather matters more for this breed than most.
Temperament
Calm · Sweet · Loyal · Easygoing
Health to watch
- Hip dysplasia
- Bloat (GDV)
- Cardiomyopathy
- Cherry eye
Owner-logged information shared via Leash Life is not veterinary advice; ask your vet about screening for these.
Questions people ask
Is a American Mastiff good with kids?
Generally yes. American Mastiffs are usually good with children when raised with them and given their own quiet space.
Is a American Mastiff good with cats?
Usually yes. American Mastiffs typically settle well with a resident cat — introduce them slowly and give the cat a high perch and a way out of the room.
How much exercise does a American Mastiff need?
A gentle daily walk.
Can a American Mastiff handle hot weather?
Carefully. Flat-faced breeds overheat fast — early or late walks only on hot days. It is sensitive; avoid the midday heat.
Leash Life keeps a American Mastiff's day — walks, meals, meds, weight — in one shared feed for the whole household, and warns on the walk weather this breed can't take. Free to start.