Picard and Data study the shed skin
Shedding or molting was the discarding of hair, fur, and/or skin. Some creatures shed regularly during a time known as shedding season. (VOY: "Parturition")
In 2370, Data was confused when he and Captain Jean-Luc Picard found shed reptilian skin that appeared humanoid, as no species then aboard the USS Enterprise-D shed their skin thusly. (TNG: "Genesis")
In 2374, Dejaren expressed his utter disgust at biological individuals, who he saw as filthy, due to his experiences being mistreated by them and his work cleaning up after their messes. Among his complaints was the fact that they were "constantly shedding your skin and hair." (VOY: "Revulsion")