cows during courtship. Bulls chase cows over long distances and even attack them face-to-face. Indian rhinos use their horns for fighting, albeit less frequently than African rhinos that largely use the incisors of the lower jaw to inflict wounds. Reproduction Captive bulls breed at five years of age, but wild bulls attain dominance much later when they are larger. In one five-year field study, only one Indian rhino estimated to be younger than 15 years mated successfully. Captive cows breed as young as four years of age, but in the wild, they usually start breeding only when six years old, which likely indicates they need to be large enough to avoid being killed by aggressive bulls. Their gestation period is around 15.7 months, and birth interval ranges from 34 to 51 months. In captivity, four Indian rhinos are known to have lived over 40 years, the oldest living to be 47. Threats Habitat degradation and floods Habitat degradation caused by human activities and climate change as well as the resulting increase in the floods has caused large death of Indian rhinos and has limited their ranging areas which is shrinking. Serious declines in quality of habitat have occurred in some areas, due to: severe invasion by alien plants into grasslands affecting some populations; demonstrated reductions in the extent of grasslands and wetland habitats due to woodland encroachment and silting up of beels (swampy wetlands); grazing by domestic livestock. Lack of site diversity The Indian rhino species is inherently at risk because over 70% of its population occurs at a single site, Kaziranga National Park. Any catastrophic event such as disease, civil disorder, poaching, or habitat loss would have a devastating impact on the Indian rhino's status. However, small population of rhinos may be prone to inbreeding depression. Expansion of other protective areas and introduction of rhinos in more areas is needed. Poaching Sport hunting became common in the late 19th and early 20th centuries and was the main cause for the decline of Indian rhinoceros populations. Indian rhinos were hunted relentlessly and persistently. Reports from the mid-19th century claim that some British military officers shot more than 200 rhinos in Assam alone. By 1908, the population in Kaziranga National Park had decreased to around 12 individuals. In the early 1900s, the Indian rhinoceros was almost extinct. At present, poaching for the use of horn in traditional Chinese Medicine is one