Patna, Dec 31 (IANS) The oldest tigress at the Patna zoo, 19-year-old Sita, has died after prolonged illness, an official said Wednesday.

The tigress at the Sanjay Gandhi Biological Park here died Tuesday. She was one of the main attractions of the zoo.

According to a zoo official, Sita was the oldest tigress in the all zoos across the country. They said the average age of a tiger in a zoo is 14 years.

Earlier, a tiger had lived upto 17 years in Patna zoo.

"Sita was suffering from knee pain since 2007 and she was brought here from Shivpuri park in Madhya Pradesh in 1999," the official said.

The Patna zoo now has only three tigers