You should research any organization before you give them money. Some very big, very well known human charities have been exposed for keeping most of donations for their so called corporate use and little of it goes the starving children or medical research or whatever.
PETA is a very controversial organization. Like most they have some ideas you will agree with and some you won't. In some cases where they have been accused of wrong doing it's very hard to tell if it was really them or bad people using their name. Just like some horrible stories of religious strife in the news these days.
You can easily to their website for their views. It's harder to dig into how they use their money unless you can find some journalistic investigation.