In the classic 1904
J.M. Barrie play
Peter Pan, the
Lost Boys are a band of small children that live under Peter's care in
Never-Never Land. They were all rescued by Peter after falling out of their
prams as infants (this being the origin of their "lost" status, presumably) and taken to his underground hideout to live.
At the beginning of the story, the Lost Boys act as a catalyst for the introduction of Wendy, John and Michael Darling. Peter Pan is introduced to these primary characters when he intentionally eavesdrops on their bedtime stories. His reason for doing this is so he can retell them to the Lost Boys. Later on, the boys play a role in injuring Wendy after being exploited by Tinkerbell out of jealousy. Then Captain Hook kidnaps the Lost Boys, making them a plot device for a daring rescue. In the happy ending, the Lost Boys are adopted by the Darling family, making them "found" boys at last.
In the 1953 Disney animated feature, all the Lost Boys are depicted wearing brightly colored pajamas/costumes resembling small woodland creatures of various types (rabbit, skunk, fox, et alii). I'm not sure if Barrie had this in mind, but I don't imagine anyone would question Disney's artistic license on the issue.