Where is 'Specialty Pets' Option?

I read there is a way to list a non cat/dog pet but I can't seem to find the option. I have reptiles and invertebrates that need caring for, but there is no way to inform the sitter of that unless I write it in the message area. If this option doesn't exist, please allow this as one! I prefer the term 'Specialty Pets' to include anything besides cats and dogs... I think 'exotic pets' is antiquated. This would include rodents, birds, reptiles, fish, insects, etc.