Manas National Park's grasslands are echoing with the calls of newborn rhino calves—a sound that once seemed impossible in this corner of India's Himalayan foothills. Nearly wiped out by poaching in the 1990s, the greater one-horned rhinos are returning, and more importantly, they are breeding. A decade-long study following 42 rhinos reintroduced between 2006 and 2021 has documented 35 births, proof that these ancient animals can reclaim their place in the landscape where they once roamed in herds of 100.
The reintroduction of greater one-horned rhinos to Manas matters because it represents one of conservation's most difficult challenges: bringing a species back from the brink of extinction. Rhinos require vast territory, stable social structures, and protection from determined poachers. That any calf has been born in Manas—let alone 35 over a single decade—signals that the reintroduced population has adapted to their new environment. "Breeding and calving are among the most important indicators that reintroduced rhinoceroses have adapted well to their new environment," said Deba Kumar Dutta, a wildlife biologist with the Asian Rhino Specialist Group at the IUCN, who led the study.
The researchers discovered something striking about the two different groups of reintroduced rhinos. Twenty-two rhinos came from wild translocations from other protected areas in Assam, while 20 were rescued as injured or orphaned animals and rehabilitated before release. These two groups behaved entirely differently in the park. The translocated rhinos, captured from the wild, spread across remote and less-disturbed sections of Manas, retaining their natural wariness and independence. The rehabilitated rhinos, by contrast, remained largely in central areas close to antipoaching camps and human settlements. "Rehabilitated rhinos are often human-imprinted and tend to remain close to human-inhabited areas within protected areas," Dutta explained. "At times they may even move towards nearby villages, mingling with cattle during the night and returning to the park in the morning."
The births tell an even more encouraging story when broken down: 19 calves from translocated females, nine from rehabilitated individuals, and five from the first generation of rhinos born in Manas itself. That last group—rhinos born in the park now raising their own young—represents a critical threshold in reintroduction success. Yet the victories are fragile. Poaching claimed some male rhinos in the early years, disrupting breeding cycles. Experts also warn that the small reintroduced population faces genetic risks from limited diversity within its breeding pool.
The path forward demands continued vigilance and active management. Yadvendradev Jhala, a retired senior scientist at the Wildlife Institute of India, has proposed that Manas's rhinos should be managed as a connected metapopulation with those in nearby protected areas like Kaziranga National Park and Pobitora Wildlife Sanctuary, also in Assam, as well as populations across the border in West Bengal. Beyond security, the park's grassland itself needs tending—invasive plants must be removed, and perennial water sources maintained to sustain the growing herd. The rhinos of Manas have already proven they can breed in the wild. Now the question is whether humans can provide the sustained support they need to thrive for generations to come.