do small dogs live longer than big dogs, and how much longer

Question
do small dogs live longer than big dogs, and if so how much longer, my sister bought my parents a 1yr old male maltese shitzu

Answer
James -

Small dogs do tend to have a longer lifespan than larger dogs.  Small dogs tend to live until they are between 12-15 years; large dogs tend to live to  between 8-11 years old depending on the breed of the dog.  

These numbers are average; big dogs can live long lives far into their teens with good healthcare and good breeding. Big dogs tend to live relatively short lives due to the development of osteoarthritis and other weight related problems.  

With good veterinary care your sister's shih tzu can live a long healthy life.

Best Regards,

Charlotte Sherrell, DVM