12 - 15 years, approximately.
This is a great site to check out:
http://www.pedigreesearch.co.uk/breed_guides/breed_description.asp
Actually, most larger breeds have a shorter lifespan than smaller breeds. However, expected lifespan varies considerably from one breed to another (some breeds are just less prone to health problems, for example) so it's worth looking up any particular breed in question before making any assumptions purely based on size.
This is a great site to check out:
http://www.pedigreesearch.co.uk/breed_guides/breed_description.asp
Actually, most larger breeds have a shorter lifespan than smaller breeds. However, expected lifespan varies considerably from one breed to another (some breeds are just less prone to health problems, for example) so it's worth looking up any particular breed in question before making any assumptions purely based on size.
