Is aggression normal in puppies? Charlie’s probably almost 4 (if not already) months old and is a little meanie. If he’s playing, and I pick him up for any reason, he’ll growl and bite me until I either yell at him or put him down. He also does this when I try to tell him “NO” or “STOP”. He just gets mad. He’s also TERRIBLE on a leash. I’m going to try a harness instead of a collar to see if anything improves. Also, he’ll bite and growl when I go to latch his collar. He’s pretty much only not a total meanie when it’s his way :/