Birth mass is the key to understanding the negative correlation between lifespan and body size in dogs
Figure 4.The difference in mass-specific lifetime energy usage is proportional to the difference in birth/adult mass ratio between breeds. Four examples of fitting Eq. 2 with empirical data and fixing intercept at zero using (A) male Italian greyhound (M=4000 gram), (B) female Colon de Tulear (M=6250 gram), (C) male St. Bernard (M=70500 gram), and (D) female Chinook (M=25000 gram) as references.