Service animal Service animals can be of many species and come in many sizes. Dogs, cats, dolphins, miniature horses, monkeys, ducks, ferrets, and parrots have all been trained to perform specific duties of a service animal, though the type of animal that may be registered as a "service animal" may vary depending on legal definitions. The people that can qualify for a service animal can have a range of physical and/or mental disabilities. A "guide animal" is an animal specifically trained to assist visually impaired persons to navigate in public. These animals may be trained to open doors, recognize traffic signals, guide
Animal studies and to understand animals as beings-in-themselves, separate from our knowledge of them. Because the field is still developing, scholars and others have some freedom to define their own criteria about what issues may structure the field. As an interdisciplinary subject, animal studies exists at the intersection of a number of different fields of study. Different fields began to turn to animals as an important topic at different times and for various reasons, and these separate disciplinary histories shape how scholars approach animal studies. In part, animal studies developed out of the animal liberation movement and was grounded in ethical questions