Unlike some other canines, it takes Mastiffs about two years on average to stop growing. At the age of two, Mastiffs would be quite close to (if not already at) their adult height. Some Mastiff parents would tell you their dog kept growing even after two years old.

How big is a full grown Mastiff?

Full grown, males start at 30 inches tall and can weigh as much as 200 pounds (90 kilograms). Females start from about 27 inches in height and weigh around 150 pounds (68 kilograms). The mastiff is massive, powerful and muscular.

Are Mastiffs intelligent?

Mastiffs are intelligent and want to please their people, but they can also be quite stubborn. If they are scared, confused, or their sensitive feelings are hurt, even by harsh words, it can be impossible to get them to do anything.