Sexual Dichromatism and Seasonal Color Variation in Furcifer angeli (E Madagascar)

Chameleons are well known for their ability to change coloration, but beyond momentary shifts, many species exhibit sexual dichromatism and seasonal variability linked to reproduction and environmental cycles. A well-documented example is Furcifer pardalis, where males become intensely colorful during the rainy season, coinciding with peak breeding activity, and later fade to more cryptic tones in the dry season due to exhaustion and hormonal changes.

In Furcifer angeli, sexual dichromatism is marked but less dramatic than in F. pardalis. Females remain cryptic throughout the year, typically in muted shades of grey or greenish tones, which provide camouflage in the canopy and understory. Males, however, show pronounced seasonal variation:

• Dry season: males adopt cryptic coloration, usually greyish or greenish, blending with the dry foliage and bark.

• Breeding season (rainy months): males shift to vivid reddish or orange tones, a conspicuous display correlated with reproductive activity. These colors are most intense during courtship and territorial interactions, serving both as signals to females and deterrents to rival males.

This seasonal dichromatism reflects underlying hormonal cycles and environmental pressures. Bright coloration during the rainy season enhances reproductive success, while cryptic tones during the dry season reduce visibility to predators and conserve energy when resources are scarce.