Board Thread:Mortal Kombat X/@comment-1084762-20150120234121/@comment-5561191-20150128145920

Oh, never mind, just found it in the wiki. I guess both of you are right, Dirtbag and Macaulyn: "Because of his state of separation from the other members of his race, and especially his matriarch, Reptile had begun to show signs of devolution" - Reptile/Original Timeline, first sentence in the sub topic Deadly Alliance.

See? According to the wiki, what can cause him to become more reptilian can be being away from other saurians or being away from his matriarch, the former having more effect. No need to quarrel so much.