More than 70% of the species' population is found in the Kaziranga National Park in India's Assam state, according to the International Union for the Conservation of Nature (IUCN), which warned that "there could have a devastating impact on the status of the species."
The 10 baby rhinos were aged between two and six months. The rhino deaths are a blow to the species' population, which was teetering at around 3,300
in the last IUCN count in 2013.
The rhinos were among 310 animals that lost their lives in the deluge, divisional forest officer Suvasish Das of Kaziranga National Park said in a statement, adding that 106 animals had been saved in a desperate rescue operation by the local community.
"We have received tremendous support from the local people of Kaziranga National Park," Das said.
The park's hog deer made up the bulk of the animals drowned, with 221 dead.
Among the rescued animals were nine rhinos, eight of which are undergoing treatment.
The besieged animals are due for some relief because floodwaters have started to recede, said Das. But 70 out of the park's 130 camps are still inundated.
The IUCN lists the greater one-horned rhino as vulnerable, one rank above endangered. Their numbers have rebounded since the early 20th century, when they were hunted to the brink of extinction
It says that rhino populations are increasing overall due to strict protections in India, but that populations in the country's northeast and in neighboring Nepal are decreasing.
The IUCN says the quality of the rhinos' habitat was deteriorating, which would "affect the long-term survival of some of the smaller populations and could jeopardize the further recovery of the species."