Jeremy is not holding a real snake, it's fake. This may be due to a low budget, or it could be that there were some difficulties letting the young actor hold a real snake. In the very next shot after he lowers the rubber snake to the floor, a real snake is shown crawling near his shoes.
Cora: (to Fred) You big slob - if that dog growls at you, it's because he detects the treachery in your miserable soul!
Fred: Cora, I'd gladly pay to get him (the missing dog) back. I'm going to train him to bite that big, fat brother of yours.
Fred: (to his wife, Cora) I only bought the mutt so you two could bark at each other and leave me in peace.