Class Specific Skills
These are the skills that can only be used by certain classes. You can't even rank in them as crossclass skills. Only the right class can take ranks in it.
Animal Empathy: Only Druids and Rangers may take this skill. You can befriend animals and magical beasts. Animal's DC is 15+Animals HD, for magical beasts is 19+beasts HD. If you succeed the check, the creature becomes your friend and fights for you.
Things to note:
1- If you fail the check by 5 or more, the creature will go hostile. (if it wasn't already!)
2- You roll 20 when out of combat.
3- Lasts 1min/level
Perform This skill can only be chosen by bards. and it determines how good your bardsong/curse song will be. Here's a table that will help you know if you need more ranks or if you're okay.
Use Magic Device: Only usable by rogues and bards.
Can be used to read casters scrolls limited to each caster class, and to use items that have restrictions. The more powerful the item, the higher the difficulty check. In order of difficulty, these are the restrictions you have to bypass with the skill: Class, Race, Aligment.
This means it'll be easier to bypass class restriction than to bypass Race restriction on an item…etc.