Ruchira Somaweera, a zoologist at the University of Sydney and principal investigator in the yearlong field study, which is funded by the National Geographic Society, said the data is still being analyzed, but the primary hypothesis is that the horns are used in communication within specific species.

Somaweera and his team focused mainly on the critically endangered leaf-nosed lizards (C. tennentii) and found that on these and on rhino horn lizards (C. stoddartii), the males of both species can move their horns slowly at a 45-degree angle while opening their mouths in a threat display.

This may aid in communication between males, he said.