mating urges

Question
i have two jack russel/sheltie mix breeds. the male is three years old and has been neutered,the female is still a pup at almost three months and has not yet been spayded. my question is evan though the male has beed neutered can he still have the urge to mate, i don't know exactly when he was fixed, but i see him trying to mount the pup from the rear and trying to "get it on"
my wife thinks i am crazy, can you shed some light on this subject?  

Answer
This actually has nothing to do with 'urges' but rather,a dominance behavior.Humping is a problem with a lot of dogs,esp males but this is because males are generally more dominant,so even neutered dogs will still have this problem. The best way to correct this problem is to use a water bottle and spray him and say 'enough' loud and firm. Often,it goes away on it's own once they decide who is the top dog