Chitwan is the home to crocodile species of Nepal mugger and gharial. Both crocodiles share habitat in the Rapti and Narayani river system. But they have some differences in habits and are evolutionary origin. Gharial prefers free flowing rivers with specialized diet depending on fish. The long snout and pointy teeth are designed to catch the fish in the river system. But mugger can be found in free flowing river as well as stagnant water such as lakes and ponds, and has generalist diet that can take large and varied prey. Gharial uses sand banks for nesting and basking whereas mugger can climb on high muddy bank also for basking. Mugger can walk distances over the land where as gharial cannot walk to distances over the land. Evolutionarily, gharial has only one close relative on its phylogeny whereas mugger has many more relatives.
Despite many differences, some unusual association has been observed during breeding time. During guardianship by parent crocodiles, the hatchings have been exchanged in the crèche. The gharial hatchlings were found in mugger’s crèche and vice versa. Through this project, we are analyzing how these two crocodiles coexist, share resources and whether mugger predates on young gharials.