Mine are that way too , specialy Apollo
he gets realy agressive, but only with big dogs, he just barks his fool head off...not at little dogs though..a big dog comes along and he acts like a Pitbull... had something realy scary happen about a month ago on one of our walks... a lab was running loose, and Rosi and Apollo where on a Retractable Lesh, well when i saw it i picked Rosi up and was going to pick Apollo up, he was jerking on the leash and before i could pick him up he litterly frayed that leash in half and he ran towards that lab with me screaming after him , he was nipping on that labs hind feet...omg i thought he was a goner... i about had a heartattack... thank god that lab must of been mellow and only snapped at him by the time i reached him... my knees where shaken 3 hrs after....