The birth of four tiger cubs made Holi more cheerful for Patna zoo authorities on Monday.

Thanks to a successful breeding programme, Swarna, a white tigress, and Royal Bengal Tiger Bheema became proud parents of the spring litter. But hold your patience, because visitors won't be able to see the cubs for some time to come.

Announcing the news on Tuesday, the authorities confirmed all the cubs were healthy and were doing well. Patna zoo director Nand Kishore said: "We had installed three closed-circuit television cameras to keep tabs on Swarna. We have not identified the gender of the newborns as we are maintaining a safe distance. Animals dislike human interference at such a stage. Therefore, we are not allowing anyone to go near the mother or the cubs. We are also keeping them away from public view. Else, the chances of cubs catching infection can increase."

Sources in the zoo said Swarna had earlier given birth to a litter of four in 2014 of whom three survived. At present, there are five Royal Bengal Tigers (male and female) in the zoo.

The zoo officials had conducted the mating programme between Swarna and Bheema three-and-a-half months ago, confirmed Nand Kishore. Both had been brought from the Nehru Zoological Park in Hyderabad under an animal exchange programme.

Zoo officials said it had taken all necessary measures to provide comfort to Swarna during her pregnancy. "Apart from installing CCTV cameras, we had increased her diet. Swarna was given 3-4kg of meat in addition to her earlier diet (9-10kg meat). Moreover, iron and calcium tablets were also being provided to her. We had also engaged the daily services of a veterinarian especially for her. In the last three months of her pregnancy, Swarna was spending most of her time in the delivery room and enclosed nursery adjoining her night house. She was only coming out in public view for around one or two hours and that too when she wished to," said Kishore.

According to zoo officials, Swarna's cubs would not be displayed for public viewing though. "Usually we don't allow cubs to be brought for public view soon after birth. They are displayed only when they turn a year-and-a-half old. Till the cubs reach that age, their mother takes care of them," Kishore said.

Visitors would be able to see the big cats in Patna zoo in a new enclosure shortly. "We are developing a new open-air enclosure for tigers, which would be far more spacious than their present cages. We would put up a see-through glass barrier in the enclosure," Kishore said.