Little is known from Sid's life other than that Sid once lived in a tree with other sloth's that always wanted to leave Sid behind when the migration occurred, using several different ways to leave him behind. What is clear is that Sid's mother always told him that "bad news is just good news in disguise" prior to abandoning him for good.

In an infamous cut scene, a crazy female sloth called Sylvia wanted to be the mate of Sid and often chased him around, although Sid was obviously freaked out by her approach and her dreams of her having a relationship with him, he was not interested in her and more then often tried to think of diversions to get rid of her. Even though, she did care and was loyal to him, he did not return the affections and he finally got rid of her, by pretending to be hunted by Diego, leaving Sylvia to realize that he did not like her at all and was greatly offended by his scam that she told Diego to eat and finally leaving him alone, when Diego wouldn't let go of Sid, he calls for Sylvia. It is not known whether or not that Sid did care for Sylvia or not as their relationship was thrown aside, for the main story to develop in construction