Chromanin

Chromanins were part of a Krikthasi's biology that allowed them to communicate by changing their body color. Imperial biologists could not decipher the language, but believed that blue and shades of green were used to represent anger and aggression, yellow was analogous to territory, while red and oranges indicated a desire to talk.

Text and facts from the “Chromanin” article on Wookieepedia, licensed under CC BY-SA 3.0. Modified for this site.