Why are you inserting many values into a single field?
Normalize that structure and create a second table to handle a many to one / many to many relationship. As it sits right now, you cannot properly select, update, or delete a single petsathome within this dataset without iterating EVERY record that's within it. If you have say 100K records, and you try searching for everyone whom has a Lion at home, you need to get every record in order to determine first if they have a lion at home. This is not ideal; doing so will see the time required even just for selections increment with each record added.
And heaven forbid if you need to delete Lion or update Dog.