Six spotted deer being translocated to the Sunderbans from a deer park in Nadia district died on Thursday. Altogether 25 deer were being translocated from the Parmadan deer park of which six died, Director of Sundarbans Biosphere Reserve, (SBR) Mr Pradip Vyas, said here. Principal Chief Conservator of Forest, Mr Atanu Raha, said around 20 per cent deer die during translocation and it was not unusual. "One reason may be that they get very excited and die due to failure of heart. Apart from this, it was very hot on Wednesday and the truck in which they were being transported was stuck in mud which caused a delay. The post mortem report will determine the exact cause of death," he said. Describing translocation as a regular drill which was going on for the last 15 years, Mr Vyas said the park was overcrowded with about 450 deer against a capacity of 150. "Unless they are shifted, their number will go on multiplying and create problems and even cause epidemics. The process will continue with more precaution," he said. He said the deer were first taken to the Sunderbans for acclimatisation and then released into the tiger reserve after a health checkup. Secretary of the wildlife NGO Nature, Environment and Wildlife Society, Mr Biswajit Roychowdhury, however, opposed the translocation for feeding tigers in the Sunderbans. "The Sunderbans is not like a zoo where deer should be supplied for feeding big cats. It is also very difficult to acclimatise deer taken to another habitat." Vyas said that a large section of people in the Sunderbans felt that there was a shortage in prey base in the tiger reserve which caused tigers to stray into villages. "We release deer in the tiger reserve assuming there is some shortage. The state wildlife board has also recommended that the prey base in the tiger reserve should be supplemented," he said.