Based on previous data, cats live longer than dogs. A recent study examined the reasons for this.

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In an international study led by the University of Bath, evolutionary differences between mammal species were examined. For this, they took the maximum lifespan potential of 46 mammal species as a basis and mapped the shared genes of the species.

The study reveals that in longer-lived species, researchers found more genes belonging to gene families related to the immune system. This suggests that this is one of the main mechanisms guiding the evolution of longer lifespans in mammals.

Brain size was also taken as a basis in the examination, in relation to which a certain trend can be observed, but the scientists also list contradictory examples. Dolphins and whales, which have relatively large brains, can have a maximum lifespan of 39 and even up to 100 years, while mice with smaller brains live only one or two years. However, there are species, including the naked mole-rat, that can live up to 20 years despite having smaller brains. Similarly, bats also live longer than would be expected based on their brain size. In these species, genome analysis found that each of them has more genes related to the immune system.

The immune system may have a highlighted role in the formation of lifespan

These results suggest that the immune system plays a central role in maintaining longer life, likely by removing aged and damaged cells, suppressing infections, and preventing tumour formation. The study shows that not only smaller mutations (for example, in certain genes or pathways) but also larger genomic changes (such as the duplication and expansion of entire gene families) may play a decisive role in shaping lifespan.

Dr Benjamin Padilla-Morales, of the Milner Evolution Centre and the Department of Life Sciences at the University of Bath, the study’s first author, formulates it this way:

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The two characteristics have a shared evolutionary path, and having a larger brain potentially offers behavioural advantages. Bigger-brained species don't just live longer because of ecological reasons; their genomes also show parallel expansions in genes linked to survival and maintenance. This shows that brain size and immune resilience seem to have walked hand-in-hand in the evolutionary journey toward longer lives.

The researchers next plan to examine the cancer-related genes highlighted in the study in order to further break down the relationship between these genes and lifespan, and to gain an even more accurate picture of why there is such a significant difference in the lifespans of mammals.