‘Thinking’ is chain of abstract ideas that may proceed without accompanying ongoing perception of relevant real stuff to which that chain refers.
‘Remembering’ may not be totally abstract. For example one real entity is currently perceived and associated things are ‘remembered’.
For example let’s say I am not thinking at all. I just see an old class fellow and suddenly ‘remember’ many associated things of old class life like daily routine of that time and other class fellows.
Animals do remember their stuff in this way. For example an animal has reached to a turn in its usual path or route. Now that animal, while physically perceiving the turn, ‘remembers’ which side to take turn.