The calf who was with its mother got severely injured and died as rhinos fought among themselves in the mating season, according to Pobitora Forest Ranger Ashok Das.
Infighting among the rhinos is a common occurrence during the mating season.
The incident took place around 3 pm, Das said.
The rhino was not killed by poachers as no bullet marks were found on its body, he said.
A veterinary doctors team rushed to the spot for conducting post mortem on the rhino.