Domestic cats age in remarkably similar ways to humans and show comparable age-related patterns of brain deterioration, according to an international collaboration between the University of Bath, Auburn College of Veterinary Medicine in the US and École Nationale Vétérinaire de Toulouse in France.
This research, published in Biology Open, offers new opportunities for studying human ageing and age-related diseases for two key reasons:
- Pet cats – unlike many laboratory animals – can live long enough to develop age-related brain changes similar to those seen in older humans.
- Cats have shorter lifespans than humans, meaning the factors affecting ageing can be studied at a much faster rate in cats than in humans.
Current research often relies on laboratory animals, where diseases are artificially induced and lifespans are limited.
For the new study, scientists led by Dr Christine Charvet at Auburn University, together with Brier Rigby Dames, now a research associate in the Department of Mathematical Sciences at the University of Bath, examined 3,754 data points collected across humans, cats and other mammalian species.
These data points covered brain imaging, blood chemistry, disease-related patterns and behavioural milestones such as eye opening and the onset of playful behaviour. The aim was to compare how ageing unfolds across humans, cats and other mammalian species.
The MRI work showed cats and humans share similar age-related changes in brain structure, including overall shrinkage, expansion of the ventricles (the hollow spaces inside the brain filled with fluid), and other structural alterations.
These brain changes are found in conditions commonly associated with ageing. Both humans and older cats can develop age-related neurodegenerative changes later in life.
PhD candidate Brier Rigby Dames: “It was interesting to see that cats show patterns of age-related brain atrophy similar to those observed in humans. These findings add to growing evidence that companion animals can provide valuable insights into ageing.”
Mapping ageing across species
Rather than using simple age ratios – where one year in humans is equivalent to a given number of years in cats – the researchers developed a sophisticated biological model based on measurable age-related changes.
This approach reveals that ageing in both species does not progress at a constant rate but instead speeds up or slows down at different life stages.
Using this model, the team found that:
- Ageing patterns later in life align particularly closely between the two species.
- A cat in its mid-teens corresponds to a human in their 80s.
- Not all animals reach the equivalent of human old age, but domestic cats do.
Implications for human and veterinary health
As a next step, the researchers would like to see greater ongoing collaboration between veterinary and human medicine, as they believe this could unlock new insights into how we age and how to improve health in later life. It could also accelerate our understanding of conditions such as dementia.
Study co-author Dr Ryan Gibson, a veterinary neurologist at Auburn University’s College of Veterinary Medicine, said a growing number of cat owners are requesting advanced brain imaging for their pets to diagnose disease, providing an excellent opportunity to study ageing animals living alongside humans in real-world environments.
He said: “This expanded clinical access creates meaningful opportunities for translational research (research that bridges the gap between scientific findings and healthcare), improving our understanding of aging and neurologic disease in ways that can benefit both feline and human patients.”
Looking to the future, Brier Rigby Dames said: “There’s potential to develop large-scale veterinary health databases for companion animals, analogous to human health databases such as the UK Biobank. These kinds of resources could enhance our ability to study ageing and disease using real-world clinical and owner-reported data collected across species.”
For this study, Ms Rigby Dames worked with the team to analyse thousands of data points across the lifespans of cats and humans while undertaking her PhD in the Department of Computer Science at the University of Bath. She contributed to the analysis of veterinary clinical records, blood-based ageing biomarkers, and neuropathology to generate cross-species age alignments.
This study is part of a long-term project called Translating Time, which equates ages across species. Dr Alexandra de Sousa, honorary lecturer in the Department of Psychology at Bath, was also involved in this study.