Growing Old Together

In it for the long haul: Capuchins are among
primates with lengthy life spans.

For many years, it was thought that humans, with our relatively long life spans and access to modern medicine, aged more slowly than other animals. Early comparisons with rats, mice, and other short-lived creatures confirmed the hunch. But now, the first-ever multi-species comparison of human aging patterns with those in chimps, gorillas, and other primates suggests the pace of human aging may not be so unique after all.

Susan Alberts, associate director at the National Evolutionary Synthesis Center in Durham and the Jack H. Neely Associate Professor of biology at Duke, coauthored the recent study, which appeared in the journal Science. The researchers combined data from long-term studies of seven species of wild primates: capuchin monkeys from Costa Rica, muriqui monkeys from Brazil, baboons and blue monkeys from Kenya, chimpanzees from Tanzania, gorillas from Rwanda, and sifaka lemurs from Madagascar.

They compared human aging rates—measured as the rate at which mortality risk increases with age—to similar data for nearly 3,000 other primates, and the data fell neatly within the primate continuum. Still, humans live the longest among primates and, unlike many other mammals, live well past their reproductive primes.

The results also confirm a pattern observed in humans and elsewhere in the animal kingdom: As males age, they die sooner than their female counterparts. In primates, the mortality gap between males and females is narrowest for the species that tend to compete less for female attention.

“We still don’t know what governs maximum life span,” Alberts says. “Some human studies suggest we might be able to live a lot longer than we do now. Looking to other primates to understand where we are and aren’t flexible in our aging will help answer that question.”