So size does matter?
Mammal’s lifespans linked to brain size and immune system function, says new study.
The researchers looked at the maximum lifespan potential of 46 species of mammals and mapped the genes shared across these species. The maximum lifespan potential (MLSP) is the longest ever recorded lifespan of a species, rather than the average lifespan, which is affected by factors such as predation and availability of food and other resources.
The researchers, publishing in the journal Scientific Reports, found that longer-lived species had a greater number of genes belonging to the gene families connected to the immune system, suggesting this as a major mechanism driving the evolution of longer lifespans across mammals.
For example, dolphins and whales, with relatively large brains have maximum lifespans of 39 and up to 100 years respectively, those with smaller brains like mice, may only live one or two years.
However, there were some species, such as mole rats, that bucked this trend, living up to 20 years despite their smaller brains. Bats also lived longer than would be expected given their small brains, but when their genomes were analysed, both these species had more genes associated with the immune system.
The results suggest that the immune system is central to sustaining longer life, probably by removing aging and damaged cells, controlling infections and preventing tumour formation.