A rhinoceros carcass was found dead in the Kazirnaga National Park on Sunday, forest officials said.
The mature female rhinoceros got stuck in the mud and died near Lengtajan camp in Kohora range of the park.
Patrolling forest guards found the carcass of the rhino.
This is the first incident of a rhinoceros death in the New Year in the park, which saw the worst casualty last year with 70 of the animals dead.
The casualty included 25 killed by poachers, 22 due to natural causes and 23 drowned in flood water.