I have recently inherited a red tail boa. He is young - maybe a year old. He is very social and usually always comfortable with me. However, Sunday when I went to feed him, he hissed at me. Then today when I took him out to handle him, he kept opening his mouth like he was going to hiss. He did it several times within 15 minutes. Then I put him back to let him relax in case something was wrong and he still did it after that but stopped after 2 times. Is something wrong? I have had him for 3 months and he has never once been aggressive to me. Any help would be wonderful. Thanks!