A symbol of longevity: Thai giant turtles can live up to 150 years. (iStock)

A penny for their thoughts.

The enclosure of two giant Thai turtles at a central China zoo has become a wishing well for Chinese tourists hoping for a long life.

Visitors at Zhengzhou Zoo have started throwing coins and bills into their tile-lined enclosure, covering the backs of the ancient reptiles, the People's Daily Online reports. Even the pond in which they live in was flooded with money.

According to folklore, Thai giant turtles, known as “millennium magic turtles,” can live up to thousands of years (scientifically it’s more like 150 years). After finding out these turtles were at the zoo, people started coming to plaster currency notes and coins on the backs of the confused reptiles with the hope that the monetary gift will bless them with long life.

Zoo workers look on as visitors shower the turtles with money and occasionally fish out the money, making room for more money gifts, according to the report.

In February, Zhengzhou Zoo was accused of abusing a seven-year-old female giant panda, Jin Yi,  leading to her death.  Chinese state media also quoted visitors who said they saw zoo officials make money by forcing the panda to pose for pictures with guests in the summer heat, whipping her if she disobeyed.