About 6 months ago, I was given a chihuahua in the parking lot of the animal shelter. The couple didn't want him anymore because they had a baby. He was maybe 2 1/2 pounds at two years old and hiss ribs/spine were extremely visible from across the room (I have since gotten him to 4 1/4 pounds and his bones don't show). He had bald patches on his neck and tail when I got him and they are still there, but they weren't itchy or dry. They seem like scarring that won't grow hair back. He wasn't neutered when I got him, but he is now. He has grown extreme attachment to me and me only, as he whines for hours when I leave the house, won't leave my lap, won't sleep if he isn't with me, and snarls/bites when anyone tries to take him from my lap or next to me. He HATES men. He goes off at any man who walks in the house even if they live there and then cowers. Are these signs of abuse/neglect, or could that just be how he is? I love him to death no matter what, I just want to understand him better.