Population and Distribution
As of 2022, the estimated population of Greater one-horned rhinoceros (Rhinoceros unicornis) stood at 4014 individuals, positioning Nepal as the second-largest habitat for this species globally. Presently, Nepal boasts approximately 752 rhinos within its borders, with the majority inhabiting Chitwan National Park, accounting for approximately 694 individuals. Additionally, populations are dispersed across other protected areas such as Parsa National Park, Shukla Phanta National Park, and Bardia National Park. Historically, the range of the Greater one-horned rhino spanned the entire Indo-Gangetic plain; however, extensive hunting and agricultural encroachment have significantly limited their habitat to Northern India and Southern Nepal. Conservation efforts initiated by the government since the early 1990s have contributed to the gradual increase in rhino numbers, although poaching remains a persistent threat. The species is categorized as vulnerable on the IUCN Red List.
Physical Characteristics
Characterized by thick grey-brown skin with pinkish folds, the Greater one-horned rhinoceros sports a single horn on its snout, reaching a maximum length of 22.5 inches. This horn, composed of pure keratin akin to human fingernails, begins to manifest around six years of age. Adult males exhibit prominent neck folds and measure between 368-380 cm in length, 170-185 cm in height at the shoulder, and weigh approximately 2,200 kg, while females range from 310-340 cm in length, 148-173 cm in shoulder height, and weigh around 1600 kg. Notably, their upper legs and shoulders feature wart-like bumps, with minimal hair except for eyelashes, ear fringes, and a tail brush. Male rhinos reach sexual maturity around 10 years of age, while females typically mature between 5-7 years. Gestation lasts approximately 16 months, resulting in the birth of a single calf, which remains with its mother for up to three years. The average lifespan of a rhino is around 40 years.
Behavior and Ecology
Renowned for their adept swimming abilities and short bursts of speed up to 55 km/h, male rhinos maintain home ranges spanning 2-8 km2. The distinctive pinkish hue of their skin arises from a dense network of blood vessels beneath the surface, facilitating thermal regulation. Despite their robust skin, rhinos are vulnerable to bloodsucking insects such as Tabanus flies, leeches, and ticks. While primarily solitary creatures, they occasionally graze and wallow in proximity to one another. Rhinos possess acute hearing and olfactory senses but exhibit relatively poor eyesight. Interactions between individuals involve gestures like head waving, nuzzling, and playful sparring. Adult males, in particular, engage in territorial disputes, predominantly utilizing their incisors rather than horns in confrontations.
Conservation and Human-Wildlife Conflict
As mega herbivores, rhinos consume a varied diet comprising grasses, fruits, leaves, branches, sedges, ferns, and aquatic vegetation, including agricultural crops like rice, wheat, maize, lentils, and vegetables. The horns of rhinos hold traditional medicinal significance. Human-wildlife conflicts arise, particularly concerning crop depredation and incidents of human injury or casualties, prompting interventions such as relief measures from the Nepalese government for affected individuals. Collaborative efforts between local communities, buffer zone management, and governmental initiatives include the installation of electric fencing, rhino-proof trenches, and barbed wire fencing to mitigate conflicts, alongside youth mobilization campaigns.
