Do big and small dogs age at the same speed? No. Big dogs usually age faster. They also often have shorter lives. Scientists studied DNA. DNA is a tiny plan inside the body. It changes as dogs get older. These changes were faster in bigger dogs. (pubmed.ncbi.nlm.nih.gov)
Think of two puppies born together. One grows big. The other stays small. After some years, the big dog may seem old first. It may walk more slowly. The small dog may still seem young. But every dog is different. Good food, exercise, and care are important.










