How can you interpret chinchilla behavior?

  How do you tell if a chinchilla is about to bite you or if it likes you? What are signs of fear, anger, happiness, etc? I literally know zip, and don't worry I don't own one, but I want to know because I work in a shelter where the have some. Please help?
when mine are feeling threatened they bark it sounds almost like a dog. or if there looking for eachother they make these wee squeaky noises.



when there in a good mood they literally bounce off the balls, when there too hot they lie down and stretch right out on their sides.



umm if theyr happy to see you they put their wee paws on the wire of the cage and will nibble your fingers and oh if there really angry they make this odd sound which is the equivalent of a growl i guess, kinda sounds like "chuff" ; said in a dog bark kinda rough voice. if they make that noise then yes they will probably bite if you stick your hand too close