Fugitive gorillas like Little Joe may be getting all the headlines, but zoos may have a more long-term problem on their hands: Stressing out their captive carnivores. A new study by British zoologists in the Oct. 2 Nature says that carnivores who normally roam over large territories – such as lions and polar bears – fare much worse in zoos than animals with smaller territories.
Ros Clubb and Georgia Mason of the University of Oxford, UK, analyzed data on 35 species of captive carnivores from published studies. They found that animals with larger territories had higher infant mortality rates in captivity than animals with smaller territories. Furthermore, the amount of time an animal spent pacing – an indicator of stress — increased in proportion to the size of its territory in the wild. Polar bears, for example, are kept in enclosures that are more than a million times smaller than their natural ranging areas.
Clubb stated in a press release: “We were surprised by the results because, until now, we had always thought that not being able to hunt was the biggest problem for zoo carnivores. But our results suggest that it’s even more important to give these animals more space.” The researchers suggest in their paper that “the keeping of naturally wide-ranging carnivores should be either fundamentally improved or phased out.”