As Shanghai residents sweat under the scorching sun amid the weeklong heat wave, animals at the city's zoo are enjoying some special treatment.

In temperatures of 37 C, air conditioning is necessary for the penguins even in the partially enclosed environment that is equipped with a cool pool, according to Jin Jun, a penguin keeper at the zoo.

"We hide three air conditioners under the rocks so that people won't see them," she said. Jin added that the spots are the penguins' favorites during summer.