The biology of ageing in dogs and humans has turned out to be remarkably similar

The findings have been published in *The Journals of Gerontology*.

The researchers analysed thousands of metabolites — small molecules produced in the body during normal cellular processes — and compared the patterns found in dogs with data from five large-scale studies of mortality in humans. The similarity was striking.

Details

The study focuses on metabolites: small chemical substances that our bodies constantly produce. They reflect what is happening at the cellular level — inflammation, metabolism, and the response to stress. By studying their patterns, scientists can look for links to long-term outcomes, including death.

The Dog Aging Project team collected blood samples from dogs participating in a large-scale, long-term study, in which owners regularly submit biological samples from their pets and complete detailed questionnaires about their lifestyle. The researchers analysed thousands of metabolites simultaneously to identify not individual molecules, but entire patterns — a kind of molecular ‘fingerprint’, as the scientists themselves call it.

“We often look at a group of molecules associated with better or worse outcomes, rather than a single one,” explained Dr Kate Crivi, the project’s lead veterinarian and a professor at Texas A&M University.

Death was chosen as the key outcome — and not by chance.

“Death is easy to record,” says Crivi. “Whereas other signs of ageing are far more vague.”

Using this clear-cut event as a starting point, the researchers can work backwards to the biological processes that preceded it.

The patterns found in dogs were then compared with data from five large-scale studies of human mortality that used a similar metabolomic approach. The molecules associated with early death in dogs matched those that predicted early death in humans. The protective markers did too.

Why this matters

Dogs have long been used in medical research, but usually as laboratory animals. The Dog Aging Project is different: it involves thousands of pet dogs living ordinary lives alongside their owners. They breathe the same air, eat similar food and move at the same pace. This makes them a particularly valuable model for studying how lifestyle affects lifespan.

Another argument in favour of dogs as research subjects is their short lifespan. The average lifespan of a dog is 12–13 years, compared to 70+ years for humans. This means that scientists can observe the entire ageing process over the course of years, rather than decades — and then apply this knowledge to humans.

The consistency of molecular patterns across several independent studies strengthens confidence in the findings. This is not an isolated result — it is a reproducible pattern.

“The molecules that are harmful to dogs or protect them from early death are very similar to those that act in humans,” says Crivi. “This shows that we share important features of the biology of ageing.”

Background

The study of ageing is one of the most rapidly developing fields in biomedicine. Researchers have long been searching for biomarkers that would allow them to predict health and lifespan before disease has a chance to develop. Metabolomics — the analysis of thousands of molecules at once — has become one of the main tools in this work.

Until now, most longevity studies have been conducted either on humans (time-consuming and expensive) or on laboratory animals such as mice (quick, but far removed from real life). Dogs occupy a unique intermediate position: they live alongside us, are exposed to similar environmental factors, and yet age significantly faster.

The Dog Aging Project is one of the world’s largest projects studying ageing in animals. It brings together tens of thousands of dogs and their owners across the United States. This new study is one of the first findings to show just how deeply the biology of ageing in humans and dogs may overlap.

Source

Benjamin R. Harrison et al., Dogs and humans share biomarkers of mortality, The Journals of Gerontology, Series A: Biological Sciences and Medical Sciences (2025).