U.S. Democratic presidential hopeful Joe Biden's campaign in February spent less than one-third the amount spent by rival Democrat Bernie Sanders, according to disclosures by the campaigns filed on Friday. Despite being outspent, Biden's campaign finished the month surging at the polls with a victory in the February-29 nomination contest in South-Carolina. In February, Biden's campaign spend $13.1-million, compared to $45.8-million spent by Sanders.