I put a question mark because I don't know if aggressive is the way to describe it... But I picked up a hognose snake at an expo, I don't know how old he is but I do know that he was used to breed and the breeder said he'd make a good pet. I held him at the expo and he was relatively calm. But just a few minutes ago I went to go check up on him and he started hissing like crazy. The second I stuck my hand in the tank he struck at it (with his mouth closed) and continued to hiss and strike the glass once I pulled my hand out. I'm more worried for him than myself. The tank conditions are; 95-97 on the hot side and 75-77 on the cooler side.