3.75 yr old Westie-Poo tries to "prowl" towards dogs when he sees them on walks & then surprise them by lunging. Why?

He started doing this around a year ago. He's been to puppy classes and socialized with other dogs from the get go (after getting his shots and all…

ASKED BY Riker on 1/4/12
TAGGED prowl, growl, walk, jump, leashed IN Leash Walking