Curious George, though universally included within the taxon of monkey, referred to as such within the body of literature which contains his various adventures, does not in fact have a tail.
Thus, it is more accurate to refer to the inquisitive primate as an ape.
 As portrayed in a selection of books and animated series, George does not have a tail. See, for instance, N Di Angelo and Mary O’Keefe Young, Happy Valentine’s Day, Curious George! (Boston, MA: Houghton Mifflin Harcourt, 2010)
 Larry, “The Monkey Song,” notes, “If it doesn’t have a tail, it’s not a monkey, if it doesn’t have a tail, it’s an ape.” http://www.youtube.com/watch?v=–szrOHtR6U [accessed March 11, 2014]