Hsinchu, July 10 (CNA) Hsinchu Zoo on Friday celebrated the 15th birthdays of its two resident Bengal tigers -- Liu-fu and Lai-fu -- with a party that included custom-made meat-and-ice cakes, well-wishes from the public and a visit from the deputy mayor.

At a ceremony outside their enclosure, Deputy Mayor Shen Hui-hung recalled that the twin male tigers were taken in at the age of five months from nearby Leofoo Village amusement park, and quickly became a favorite attraction of children visiting the zoo.

Since taking office in 2014, Mayor Lin Chih-chien has increased funding for the zoo by 60 percent to provide the animals with better quality food and medical care, and oversaw a two-year project to refurbish zoo facilities, Shen said.

Meanwhile, Zoo Superintendent Yang Chu-yuan led the crowd in singing "Happy Birthday" to the tigers and introduced the custom-made "cakes" prepared by the zoo's nutritionists.

To prevent the tigers from overindulging in their favorite food, strips of raw beef were placed on large blocks of ice made from a mixture of water and blood to keep them hydrated and cool in the summer heat, Yang said.

According to the zoo, Bengal tigers have an average lifespan of 15-20 years in the wild and 20-25 years in captivity.

Around 4,000 of the endangered subspecies remain in their natural habitat in the Indian subcontinent, with roughly three times that number in captivity, according to the zoo's website.

Hsinchu Zoo -- the oldest in Taiwan, built in 1936 -- reopened on Dec. 28 last year after a two-year project to update facilities for the 70 animal species housed there.