Wetenschap - 7 maart 2002

Zoo is no place for polar bears

Zoo is no place for polar bears

Adapted to living near the north pole, with instincts geared to catching seals and roaming for hundreds of kilometres, the polar bear is not suited to life in a zoo, says Wageningen biology student Roald Severens. He found evidence in Ouwehand Zoo, where stressed polar bears walk around like zombies.

Stereotypic behaviour, biologists call it, when animals in the zoo just walk around in circles, with their eyes blank, not noticing anything. The polar bears in Ouwehand Zoo close to Wageningen also fall victim to this sad phenomena, according to Roald Severens and Wouter Minkhorst who studied the behaviour of these animals in captivity.

Posted next to the polar bears' quarters from dusk till dawn, the students saw the bears regularly walking around in circles. One of them even shows stereotypic behaviour for about sixty percent of the time. "Once we observed Wash - a female ? walking around in circles for 247 minutes without stopping. She completes three circles a minute," says Minkhorst. The bear even wears out the concrete floor with her steady pace.

The stereotypic behaviour comes into play especially around feeding time, discovered Severens. In the wild, the polar bears take a lot of time to find food, but in the zoo food is given to them. This goes against the instinct of the animals. After feeding time they still want to eat. They get stressed and start walking in circles, says Severens.

Climate a problem

The polar bears at Ouwehand Zoo recently got larger accommodation, measuring about 80 by 80 metres but it is clearly small compared to what they have in the wild. Severens: "A polar bear in the wild walks a lot. In a year it can easily cover a thousand kilometres in search of seals. What you also have to bear in mind is that polar bears have a difficult time in Holland because of the mild climate. Polar bears typically retain a lot of heat in their body and cannot release it easily. In summer in Holland you see the animals panting with their mouth hanging open, and they are far less active."

There are zoos that adapt the climate of animal accommodation, for example by creating snow, says Severens. "But this costs millions. Ouwehand Zoo does not have that much money." At the moment, there does not seem to be a solution to the stressful conditions of the polar bears in Ouwehand Zoo. But compared to another inhabitant of the zoo, a snow panther, the polar bears are not doing so badly at all. The panther is alone in a cage of about six by six metres and spends much time prowling along one of the sides.

Hugo Bouter

Photo Roald Severens