First report of rapid eye color change in a non‐avian tetrapod

Abstract

AbstractLike coloration of the integument, eye color can be a significant but understudied component of communication and reproductive behavior. Eye color can change with sexual maturation and become sexually dimorphic, but in a few birds and fish, eye color can also change rapidly in response to the environment. There are few cases of the latter, and we report here several instances of such change in eye color in the Eastern box turtle (Terrapene carolina carolina), the first non‐avian tetrapod in which this capability has been reported. In male turtles, the iris changed from a pale yellow color (often characteristic of juveniles) to a bright red color (characteristic of mature males) in a period of <5 s. The nature of the color change is similar to that observed in some birds and suggests a common mechanism and/or adaptive role, which could be further explored in Eastern box turtles.