I am theater professional, who is becoming a science fan.  I am currently working on a script for a tour though some animatronic mammals of the Cenozoic.  I had someone ask the question how can you tell the fossils have been found are those of a mammal?  I then began to wonder myself.  Any info you might have would be great.

Thank you,

Fossils are only ancient preserved bones, so you identify them the same way you identify any bones: by comparison with other specimens whose identity you already know. The skeletons of many, many mammals have been illustrated and described, and it's not too hard for someone who's familiar with extant animals to recognise the remains of exinct ones.