Wild chimpanzees show human-like cognitive decline with age

By
Lindsey Valich
Published
October 28, 2025
Three wild chimpanzees of varying ages gather and use rocks to crack nuts.
STONE AGE: Western chimpanzees using stones to crack open oil palm nuts. Tracing long-term behavior changes in chimps—including their use of tools—can yield fundamental insights about aging and cognition. (Getty Images / Anup Shah)

For decades, scientists assumed only humans experienced dementia. Now, new field observations suggest that wild chimpanzees—our closest primate relatives—may also show signs of cognitive decline with age.