Blue is a relatively uncommon color in the reptile world, so it attracts my eye (and camera) whenever I see it. As my explorations in Madagascar have taken me into January - the first full month of the rainy season for most of the country - I've been noticing how some chameleons whose appearances I thought I knew well surprised me by donning a flush of blue. This is primarily a sexual signal, although in males whether it's to announce their dominance to other rival males, or to attract females, is still not completely clear. The females assume it, often in concert with other 'odd' colors, to warn off amorous males once they are gravid and no longer interested in mating.
The animals are (clockwise from left): A male Calumma oshaughnessyi ambreensis on Mt. d'Ambre, Jan. 2002; a male Furcifer verrucosus near Betioky (southwest Mad., late Dec. 2001); and a female Furcifer verrucosus near Ambovombe (southeast Mad, Jan. 2001).