Science & Tech · Science & Environment · 1 hr ago
DNA study finds large dogs age faster at the molecular level
Researchers found that larger dogs age faster at the molecular level, helping explain why they tend to have shorter lives than small dogs.
The study examined 894 pet dogs in ordinary American homes who were part of the long-running Dog Aging Project.
Researchers measured chemical tags on DNA, which change in predictable ways with age and can be used to estimate biological age.
Male dogs also showed signs of faster aging, and each year a dog’s molecular age exceeded its actual age was linked to about a 15 percent higher risk of dying within two years.
Many age-related changes were found in repeated stretches of DNA that can copy themselves and move elsewhere in the genome.
The DNA clock may help veterinarians estimate the age of dogs without recorded birthdays, but it cannot predict an individual dog’s lifespan.
Researchers hope understanding these changes will eventually help find ways to extend dogs’ healthy years.
A study of 894 dogs found that larger dogs show signs of faster aging at the molecular level.
Researchers analyzed chemical marks on DNA from dogs enrolled in the Dog Aging Project.
At the same calendar age, larger and male dogs had DNA profiles associated with older animals.
The molecular-age clock predicted age to within about a year on average and was associated with survival.
Researchers said the findings describe patterns across groups, not how long any individual dog will live.
- Who
- Researchers Blaise Mariner, Brianah McCoy and Noah Snyder-Mackler at Arizona State University.
- What
- A study found that larger dogs age faster at the molecular level, based on chemical marks on their DNA.
- When
- The DNA samples were sequenced between 2021 and early 2024. The article was published on 2026-10-25.
- Where
- The dogs lived in ordinary American homes; the study was conducted by researchers at Arizona State University.
- Why
- The researchers examined DNA changes to help explain differences in aging, lifespan and health between dogs.
This story does not have two clearly opposing sides.
Researchers sequenced 1,640 DNA samples from the dogs.
Earth.com published its report on the study.
- Dogs studied
- 894
- DNA samples
- 1,640
- Age-clock accuracy
- Within about a year on average
- Dogs that died
- 121 of 894 died within two years of giving a sample
- Molecular age and mortality
- Each year above actual age was linked to about 15 percent higher risk of death within two years
What people are saying
For people who love large dogs, our findings offer a biological clue to why their time with us is often shorter,