â??Muskrat Loveâ? may have been a hit in the 1970s, but â??Cotton-Top Tamarin Affiliativeâ? doesnâ??t have quite the same Top-40 potential — unless you happen to a primate. The “song” — part of a collaboration between a University of Wisconsin-Madison professor and a musician — certainly got some Wisconsin-based Cotton-Tops, small monkeys normally found in the forests of northern Columbia, going. The researchers described how music could influence the monkeyâ??s behavior in a study published in this weekâ??s Biology Letters journal.