Despite the (positive) racist stereotype behind this assumption (the idea of the "noble savage"), Tashtego’s character also illustrates the frustrating illogic of racism and racial hierarchies. As the harpooneer on Stubb’s whaling boat, it is Tashtego who strikes the first whale that we see killed in the novel--but the credit for the hunt and the kill goes entirely to Stubb.
It is also Tashtego who sights Moby Dick at the same moment that Captain Ahab does at the end of the novel--but Ahab insists he saw the White Whale first, denying Tashtego the promised reward of the gold doubloon.
For more on the subject, see Raoul Trujillo as Queequeg and The Best Indian Books.
Below: Queequeg, Tashtego, and Fedallah.
George Klauba, Tashtego, 2003, acrylic on panel.
Mark Milloff, Quequeeg Rescues Tashtego From the Head of a Whale, oil on canvas, 1986.