The shifts in perspective throughout the first eight chapters of Life of Pi give the reader a mix of direct and indirect characterization.
In terms of direct characterization, the audience receives physical descriptions of an older Pi through a third-person narrator:
He's a small, slim man - no more than five foot five. Dark hair, dark eyes.... Expressive face. Speaks quietly, hands flitting about.
Otherwise, at least early in the book, the reader receives very little direct description of Pi. This seems to indicate that Pi is more concerned with the make up of his mind, his character, and his outlook, than with his physical comfort or disposition.
Conversely, Pi delivers a wealth of indirect characterization in these early chapters. He demonstrates a love of learning, social sensitivity, personal advocacy, judgement of character, and a respect for knowledge (both scientific and mystical). This information is demonstrated through conversations with other characters and through exposition.