The Pretoria Zoo says it's turning to technology with infra-red cameras to search for a two-meter-long (6.5-foot-long) black mamba snake that escaped from its enclosure a week ago.

Marketing manager Craig Allenby of the zoo in South Africa's capital said Thursday the missing snake probably is in the roof of a service building behind its terrarium. That has not stopped fearful callers to radio talk shows discussing the nearly always fatal results of a bite from one of the world's fastest and most venomous snakes.

Zookeepers realized last week that the mamba's enclosure was empty. They have been unable to search the roof area where they suspect it is preparing to hibernate.

The cameras to be used detect infra-red radiation emitted by bodies and objects, even cold-blooded reptiles.