the new ADA allowing service cats excerpt here.
In the NPRM, the Department used the term "common domestic animal" in the service animal definition and excluded reptiles, rabbits, farm animals (including horses, miniature horses, ponies, pigs, and goats), ferrets, amphibians, and rodents from the service animal definition. 73 FR 34508, 34553 (June 17, 2008). However, the term "common domestic animal" is difficult to define with precision due to the increase in the number of domesticated species. Also, several State and local laws define a "domestic" animal as an animal that is not wild.

The Department is compelled to take into account the practical considerations of certain animals and to contemplate their suitability in a variety of public contexts, such as restaurants, grocery stores, hospitals, and performing arts venues, as well as suitability for urban environments. The Department agrees with commenters´ views that limiting the number and types of species recognized as service animals will provide greater predictability for public accommodations as well as added assurance of access for individuals with disabilities who use dogs as service animals. As a consequence, the Department has decided to limit this rule´s coverage of service animals to dogs, which are the most common service animals used by individuals with disabilities.

I have a service cat and let me tell you I think you are the most ignorant dumb people that have ever thought about service animals let me correct all of you on your ignorance. The ADA is the law NO EXCUSEs. in the ada your service animal must do tasks to mitigate your disability. If the cat does that then it is a service cat! I have PTSD and I am not a vet but seeing my mother and my brother almost beaten to death by my father every god damn day it can do that to you. So dont give me that bull that it isnt real just because you dont have the pleasure of being raped by your own parent doesnt mean that mental illness isnt real. I have taken my service cat with me where ever it goes it mitigates my disability it is NOT a pet! which is why i dont have to pay a pet fee in my apartment for her. Now him saying buffering might be one of the things she does for him but that alone is probably not what she does because that will not stand up in court. Its ignorant people like you that dont understand that you have to let my cat in and i will call the police on you if you dont. it is my job to educate you about service animals unfortunately. I will say that if any of you own a buisness and tell me that you will not allow my PSD friends and my PSC. I will call all of them and show up at your door demanding that you let us in and then if you dont i will call the police and you will go to court and have to pay fees and fines for not letting me in. I just cannot say how much reading this infuriates me. You all are a disgrace to humanity and the vetran who said PTSD isnt real i dont believe you should be allowed in the military with your stupid attitude your the military people that i look at and all i see is an ass whole i hope you all get taught a lesson sometime soon about the disabled people!!!!!