– You can think of these chimpanzees as bullying, independent and a little unpredictable, says Alexander Weiss, PhD in psychology at Edinburgh University and co-author of a new study on the personality of chimpanzees.
37 years of observations
In Gombe National Park in Tanzania, field researchers have long observed chimpanzees in the wild. After analyzing 37 years of data, Alexander Weiss and his colleagues examined the relationship between male chimpanzee personality traits, rank, and reproductive ability.
The study showed that the chimpanzees with more dominant and careless personality traits had more offspring than their calmer and more caring mates. In addition, the researchers could see that the dominant chimpanzees reached higher ranks within the herd.
To investigate the relationship between personality traits and rank, the researchers not only wanted to find out how a chimpanzee behaves in a group, but also how chimpanzees relate to each other. Therefore, the researchers studied so-called pant-grunts, which is a sound that the chimpanzee makes to another chimpanzee when it shows its inferiority.
“You’re the boss”
– When two male chimpanzees meet, one of them will give off a pant grunt that means something like “Hey you’re the boss”.
The dominant chimpanzees in Gombe National Park also seem to retain the benefits of their perhaps slightly disruptive personality throughout their lives. They retain their high rank and continue to have many young even when they are old.
– If you visit a zoo, keep in mind that the animals’ personalities probably differ as much as your personality differs from that of the other people at the zoo.