I have a friend who brought home a lab rat from medical school and kept him as a pet. I can't stand rodents but that big boy was so sweet, friendly and smart everyone liked him.
Keeping pet rodents and reptiles is NOT acceptable when selling your home. It's doesn't matter how sweet Templeton may be, potential buyers won't be around long enough to become acquainted.
Successful marketing of your home involves making it appeal to the broadest audience. Buyers do not react positively to reptiles and rodents.
There are buyers who will not set foot in a home with snakes and even more who will go in but are completely distracted and focused on getting out of the house. This means there are fewer people who will be interested in your property and a lower sale price if any at all.
Relocating pets during while your home is on the market is stressful but far better than dragging out the selling process.