Take a look at the sentence again:
During the summer when a variety of fruit is in season, Melville always
avoids the fresh peaches, the fuzzy skin brushing against his lips makes
Melville think that he's eating a small
rodent.
You need no correction between think and that. The fuzzy skin brushing against his lips makes Melville think is a main clause. That he's eating a small rodent is a subordinate clause. You must connect a subordinate clause to a main clause. When the subordinate clause follows the main clause, as in the example above, you generally need no punctuation.
Go back to the sentence to try again.