Research carried out on house sparrows showed how changes in DNA that are linked to ageing and lifespan take place as body size gets bigger.
The research centred round telomeres, special DNA structures that all animals, including humans, have at the ends of their chromosomes.
The study, conducted jointly by the University of Glasgow and the Norwegian University of Science and Technology, found that skeletally bigger house sparrows had shorter telomeres.
Pat Monaghan, regius professor of zoology at the University of Glasgow, who supervised the analysis, said: “Growing a bigger body means that cells have to divide more. As a result, telomeres become eroded faster and cells and tissues function less well.
“Being big can have advantages, of course, but this study shows it can also have costs.”