When the Oustalet's Chameleon Female Gets Gravid

Chameleons do not primarily change their coloration to blend with the environment, but use it mainly for communication and thermoregulation purposes. A very special case occurs when females, due to changes in hormonal levels, begin to show a very specific coloration after conception. The purpose of this discoloration is to deliver a clear message to the males that they are gravid and do not want to be disturbed by their presence. Males can limit the females' access to resources, which is critical since they need to feed a lot. This coloration also serves to prevent males from attempting to mate, as such attempts are stressful and meaningless and can hurt the quite vulnerable gravid vemale.

Under normal circumstances, males who live in close proximity to females understand these signals and respect their messages by leaving them alone. In various species, the female coloration during the gravid period is quite spectacular. Many species within the genus Chamaeleo and Furcifer exhibit striking patterns, with gravid females often displaying warning yellow or orange patterns on dark background on their bodies. 

The female of the giant Oustalet chameleon from Madagascar shows the typical pattern of the species, featuring a combination of dark black and red patterns, and light blue hues on the head and flanks.

Females adopt this type of coloration immediately after conception and usually show two versions of it: one that is more cryptic and lighter, consisting of brownish and greenish tones, and the other, more conspicuous, which they use when they need to signal their gravid state to an approaching male. This more vibrant version typically consists of a highly contrasting pattern with a dark black background, making the shiny patterns even more pronounced to ensure the message is clearly visible and communicated.