Scientists have put forward a number of theories as to what the crest was used for. The most likely explanation is that it enabled the parasaurolophus to make loud trumpeting calls.

Parasaurolophus could walk on either two or four legs. Its tail was thin, but unusually tall.

Scientists think that the tail – and the crest – may have been brightly-coloured. This could have been used by males in order to attract females, or to help parasaurolophus to stay together in the undergrowth.

Three species of parasaurolophus are currently recognized, namely Parasaurolophus walkeri, Parasaurolophus tubicen and Parasaurolophus cyrtocristatus.

Each species of parasaurolophus had a unique crest structure. It is believed that the precise shape and colouring of the crest may have changed according to the age or sex of the animal.

Inside the crest were passages through which air from the nostrils could pass. These tubes led from the nostrils to the end of the crest then back down into the skull.