The Bengal Tiger, which was found dead at the Sundarbans in Bagerhat, likely died of natural causes, officials said on Saturday after the autopsy.
Dr Tofazzel Hossain, a livestock officer, performed the autopsy on Saturday and concluded the big cat has died of old age, reports UNB.
Earlier, the livestock officers of the Forest Department and Wildlife teams examined the dead tiger and sent its teeth, liver, lung and others to Dhaka for forensic tests.
On Friday, the tiger, estimated to be around 15 years old, was found dead near Dublar Char by the Forest Department.
It had no marks of injury on its body.
The 2015 tiger census recorded a population of just 106 in the Bangladesh part of the Sundarbans mangrove forest, which rose to 114 in 2018.
On the other hand, 126 of the endangered big cats died in India last year, the most since it began compiling data a decade ago.
India is home to around 75% of the world's tigers.
In 2010, Bangladesh, India and 11 other countries signed an agreement to double tiger numbers by 2022.
Besides, a number of tigers were beaten to death by people while some others due to natural disaster and some due to old age.
Skins of 20 tigers were recovered during this period.