I like how I have never encountered the word propitiation before (I can surmise its meaning) but knowing the proper definition of a word prior to encountering it is unnecessary in many circumstnces of the LSAT

Im curious about this: do we always presume that a tiger is a mammal in this question, or is there a potential question where we are not told a tiger is a mammal and must rely on common knowledge that it is a mammal. Is it always safe to presume these things in the LSAT.