I believe Hobar is correct. While the ADA defintion of service animal is limited to dogs, there is a separate provision in the regulations about miniature horses but as MarciAnn points out, it does not apply to cruise ships. Rather, that provision applies to the ADA regulation for governmental/public entities, not commercial. Cruise ships are commercial. I would Ike to think MarciAnn is correct in that Seabourn is not allowing certain guests preferential treatment to flout the rules as others have suggested, it may not be Seabourn but rather the passenger himself or herself who takes advantage (“games the system”) since it is not difficult to do given the limitations on what a business may ask an individual.