When Auntie Rose died in early 2007, she was the oldest wild chimpanzee known to humankind. At around 63 years old, she was very elderly for a chimp, and her final months had been difficult. “She had lost all her body hair, and she just crawled about in the forest,” recalls Emily Otali, field director of the Kibale Chimpanzee Project in Uganda and a National Geographic Explorer. “I felt sorry for her.”

Still, until the very end, Auntie Rose had been fending for herself. Adult chimpanzees rarely share food, not even with the old-timers, so elderly animals have to keep up the effort required to find their own meals. Aging animals in the wild are less active, Otali says, and may become a bit feeble too, losing muscle mass as they age. “But they handle old age much better than we do. They just power along, it’s amazing.”

Meanwhile, chimps at biomedical research facilities in the United States were considered to be geriatric once past the age of 35. Four facilities kept hundreds of chimpanzees for years, conducting experiments designed to help us cure or prevent human disease. When these captive animals started developing familiar ailments associated with aging in humans, such as heart conditions and diabetes, researchers marveled at how similar our closest relatives were to us.

At the Ngamba Island Chimpanzee Sanctuary in Uganda, chimpanzees confiscated from poachers live in large tropical forest enclosures, where they are free to roam. They receive a yearly health check, in which veterinarians sedate the animals, providing the perfect opportunity to collect data on the aging process.

“Based on studies in captive populations, scientists thought chimpanzees had very high levels of cholesterol,” says anthropologist Alexandra Rosati of the University of Michigan. But in a recent study, Rosati and her colleagues found that chimpanzees at the Ngamba Island sanctuary had much lower cholesterol than lab chimps.

Similarly, other markers of cardiovascular health risk, such as body weight, were lower in the chimpanzees of Ngamba Island, says Rosati. The explanation, she adds, may be that they move around more than the lab chimps could. They also eat more fruits and vegetables, some of which grow wild in the enclosure, and less of the nutrient-dense chimpanzee chow that was a common staple in labs.

Read the full article at National Geographic.