The Question and Answer section for The Jungle Book is a great resource to ask questions, find answers, and discuss the novel.
Major themes addressed in the novel, Mowgli's Brothers, include nature versus nurture, reason and knowledge, abandonment, laws and codes, and discrimination and envy.
These are actual rules and legal codes the animals in the jungle live by. One is that animals must stick with their own kind.
I'm not sure what you mean by monkey "lane".