Watch dog and defence dog.
Nature: A true American Staffordshire Terrier is so aware of its strength and of its potential that it literally knows no fear.
Particularity: President Roosvelt raised them and promoted their images on military postings of the First World War. During the conflict they became popular and not only among the troops. A Staffordshire Terrier called "Stubby" saved a division of the army by warning of gas attacks.