Are the chimpanzees in danger?

Chimpanzees are highly intelligent apes. They share more than 98 per cent of their DNA with humans. Scientists have shown that chimpanzees use tools and other things to achieve their goals. For example, in the wild, chimpanzees remove the twigs from a branch and use it for fishing termites out of a termite mound. They also use stones to crack hard nuts.

Much of the scientific knowledge about chimpanzees comes from the chimpanzee troop in Arnhem. In 1971, Burgers' Zoo was the first zoo in the world to house a group of chimpanzees with several adult males, just as they live in the wild. Several experts were convinced that chimpanzee males would be too aggressive and did not believe it would work. However, the initial scepticism soon turned to admiration and curiosity; since the troop's inception, scientists have studied the behaviour of these animals. Famous scientists such as Frans de Waal and Otto Adang spent a lot of time along the chimpanzee canal in Arnhem. Their scientific work frequently led to groundbreaking insights and significantly changed our view of our closest relatives.

Among other things, they have shown that chimpanzees are good at working together to achieve something, even when one of the individual animals does not benefit from it (altruism). Chimpanzees also appear to be capable of reconciliation: they settle conflicts and "forgive" the aggressor for their behaviour after a while. Otto Adang even drew striking comparisons between a group of chimpanzees on the warpath and a group of football hooligans on their way to a confrontation with rivals! His insights are still used in police training on group behaviour and de-escalation methods of group aggression.

One of the behavioural experiments conducted on the chimpanzees involved observing how the animals reacted when they discovered a potential enemy in their vast, outdoor enclosure. To this end, a lifelike, stuffed toy leopard was positioned in a visible location in the outdoor enclosure. The "leopard" was discovered soon after the chimpanzees emerged from their indoor enclosures, causing great excitement and turmoil. After a lot of screaming and intimidating behaviour (especially from the males) from a distance, the apes became very curious.

Slowly but surely, with cautious steps, the vanguard of the group approached the potential threat. In particular, a half-grown male—whose status in the group was rising—showed the most cheek and started throwing sticks at the "leopard". When there was no response, the males grew bolder and came closer and closer until the first heroic blow was struck and the stuffed toy fell over. It was not long before the toy was expertly torn apart amidst loud cheers, joined by more and more brave participants. The chimpanzees had a lot of fun, and "the danger" was gone!

In a zoo where rival troops are just as rare as real threats, a fake threat can stimulate the group to act together and promote bonding.