Rhinoceros horn bill have upward curve casque on their bill, just like rhino horn, native to rain forest of Indonesia, Thailand and Singapore. This casque is largest one among horn family, which also brings this common name for them. Male’s casque are little bigger than that of female birds.

It took almost six for the completion of growth of casque over the bill of rhinoceros horn bill. They also this casque to amplify it’s calls, becomes so loud,can hear throughout the forest