A paleontoligist is a scientist that studies priehistoric life.
Many professional jobs do not have the concept of "hours" - the work continues until it is done. With a palaeontologist field work is either working from dawn to dusk in unpleasant conditions then far into the night writing notes, travel to and from the adverse locations, or (once back to home base) getting notes in order to present the results. Time left over will be used in further study, budget preparation or similar.