Personally, I have had large dogs and small dogs.
The large dogs don’t live as long as the small ones do for some reason.
We had a mixed breed dog, part Chow part whatever, that didn’t live but about seven years but was very smart.
We had a Chihuahua that lived 20 years and a Lhasa Apso-Shih Tzu mix that lived 18 years..............
Exactly.
All our big dogs fell over dead at 8 to 12 years old. All our little ones hit 20 or so.
I have been hunting since I was little. Most canids don’t make it past 4 or so. Wolf and coyote and fox. They live long enough to procreate and game over. Tooth fang and claw.