Chimpanzees are amongst our closest living relatives – in fact, we share about 99 percent of our DNA with them. Now, it seems they also have unique personalities that remain stable over time, just like us.
Many years ago, Jane Goodall pioneered the idea of chimpanzees having personalities. “It isn’t only human beings who have personality, who are capable of rational thought and emotions like joy and sorrow,” she said. She is also famous for discovering that chimps use tools.
Goodall focused on chimpanzees from the Kasekala community in Tanzania’s Gombe National Park. In research conducted in 1973, a group of researchers quantified the personalities of chimps from this community by rating 24 unique traits.
The researchers found female chimpanzees to generally be more trustful, timid, and depressed. Meanwhile, males were more aggressive and gregarious. However, there were still vast differences amongst the sexes. One particular female, Passion, killed and ate at least four infant chimps in 1975. The researchers decided to exclude Passion from their results due to her unusually “disturbed” behavior.
Despite these findings, the idea of animals having personalities didn’t really pick up until the late 1990s. Now, a research team led by the University of Edinburgh has looked back at this ground-breaking research to assess whether chimp personalities might change with time.
“It’s the most famous groups of chimpanzees in the world, and I thought this was a terrific opportunity,” lead researcher Alexander Weiss told National Geographic.
Weiss and his team first headed to Tanzania back in 2010 to meet with 18 current and retired field assistants who knew the chimps there and had studied them, some for as long as 35 years.
“It was pretty awe-inspiring – I knew about these field assistants, having read work by Jane Goodall before,” said Weiss. “It was an amazing privilege that they took the time to help out with this.”
These researchers rated the personalities of 128 chimpanzees, some of whom are no longer around today. They looked at 24 different traits, such as fearful, curious, greedy, jealous, playful, helpful, manipulative, and gentle.
Weiss’ team then compared the new survey results with the results from 1973 and found consistencies in the chimps’ personalities. This means that although they might change slightly with age, chimps have personalities that remain relatively constant throughout their lives, just like we do.
Weiss and his colleagues collected a large amount of data, and have published it in the journal Scientific Data. They hope their findings might help other scientists to better understand personalities in people, and the effects they have on things like reproductive success.
“I don’t have enough time in my life to do everything that can possibly be done with these data, so why not let other people explore them?” explained Weiss.
“That’ll be really cool to see,” he added.