By Waliur Rahman
BBC News, Dhaka
Officials are concerned about in-breeding at Dhaka's zoo.
Wildlife officials in Bangladesh say they are planning to introduce birth control to curb the growing number of tigers and lions in Dhaka zoo.
There are now 36 tigers and lions in the zoo which has space for only 16. Half of the food budget is being spent on the big cats, officials say.
They have yet to decide whether birth control pills or hormone injections will be used to limit unplanned births.
Officials say a final decision on the method will be taken within two months.
The zoo's curator, Mafizur Rahman, told the BBC that several options, including birth control measures, were being considered as a way of limiting lion and tiger numbers.
Officials want to emulate birth control measures carried out by London Zoo
Mr Rahman said the big cats were also in-breeding, which could damage the health of future animals.
"This can be risky as such mating causes the increase of lethal genes among the future generation, leading to premature deaths due to various diseases," he said.
Bangladesh does not have the necessary forests where surplus big cats could be released, he said. Requests for other zoos in Bangladesh and abroad to take on some of tigers and lions had met with little response.
"Our preliminary decision is to go for using birth control pills or hormone injections. But we are also gathering information on how the zoos in other countries are coping with the problem," Mr Rahman said.
According to wildlife experts, London Zoo is also using birth control methods to limit the number of its tigers and lions.
Mr Rahman said they do not want to introduce any permanent method of birth control.
"Pills or hormone injections will not harm the sexual desire of the tigers and lions. They will be able to breed once the birth control methods are withdrawn," he said.
The zoo's medical board is due to sit in a couple of months to decide on which method will finally be employed to limit in-breeding and unplanned births.