To understand words you don't know, you can always use a dictionary or a credible website to help. If that definition doesn't make sense, ask a teacher, parent, or peer to help clear it up for you. Finding what sources are good and what sources aren't, you have to think of several things. If it is outdated, on a website with open editing, or not written by an expert, it is always a good idea to find another source. Hope this helps!
It is shown that the animals have human-like intelligence, and as a result chose to leave their home, but I'm not sure if there is enough evidence to prove any theme.