Animal rights activists angry after orangutan who tried to flee German zoo is shot dead

In this file photo, a young orangutan hold on to the bars of a cage at the Duisburg Zoo, western Germany, on Wednesday April 14,2010. (AP Photo/Frank Augstein)

BERLIN -- Animal rights activists have reacted angrily to the killing of an orangutan who tried to escape from a zoo in western Germany.

The endangered ape managed to slip out of his enclosure at Duisburg Zoo on Monday and tried to flee over the outer perimeter fence.

Keepers shot the male orangutan dead before he could escape, saying a sedative would have taken too long to take effect.

The German Animal Protection Association called on the zoo Tuesday to investigate the incident.

Marius Tuente, a spokesman for the group, said the case showed it's unethical to keep highly intelligent animals such as orangutans in captivity.