[algernonpj]

And why do big dogs generally not live as long as smaller dogs?

Don't know if it is true, but I have been told that their hearts give out. In other words the hearts of giant breeds are not proportionally larger, and work much harder than the hearts of smaller breeds.

[chris_bdba]

That is exactly what our vet told us that big dogs hearts are not much bigger than an average dog’s heart is and that it just works itself to death.Their joints give out like a larger person’s do because of their size.I do wish they lived longer, 8-10 years just isn’t long enough though we did have one Great Dane live to be almost 13.