Rostral Symmetry and Rain‑Driven Emergence in the Rhinoceros Chameleon

Furcifer rhinoceratus is a northwestern Malagasy species, with distribution centered around Ankarafantsika's dry deciduous forests. The defining feature is the rostral appendage: a single, laterally compressed "horn" present in both sexes. In females it is smaller but still distinct, which is unusual among chameleons where female rostral structures are typically absent or vestigial.

Reproductive activity is closely tied to seasonal transitions. Courtship and mating occur at the end of the dry season and into the onset of rains, when humidity rises and conditions favor successful oviposition. Females deposit clutches in friable soil during the rainy season. Embryonic development proceeds through the wet months, and hatching is synchronized with the early rainy season. Neonates emerge precisely when insect prey is abundant and microclimatic conditions are favorable, an adaptive strategy that maximizes juvenile survival in a strongly seasonal environment.