Complex sentence: The bright yellow or orange underside of crested newts is an aposematic coloration which can be presented in case of perceived danger; in such a posture, the newts typically roll up and secrete a milky substance.
Split into simpler sentences: The bright yellow or orange underside of crested newts is a warning coloration which can be presented in case of perceived danger. In such a posture, the newts typically roll up and secrete a milky substance.