Under the Americans with Disabilities Act (ADA), the use of service animals could be considered a reasonable accommodation for a disability. Service animals are usually dogs, but can be other species of animals.
Title III of the ADA governs places of public accommodation, whereas Title I governs employees in the workplace. Under Title III, animals being used for purposes of emotional support, therapy, comfort or companionship are not considered service animals because they have not been trained to perform a specific task. Under Title I, however, an emotional support animal could conceivably be considered a reasonable accommodation for an employee with a disability, such as a veteran with PTSD.
When confronted with an employee’s request for use of a service animal, an employer should treat the request like any other disability accommodation request, on a case-by-case basis. Unless the disability and need are obvious, you can ask for reasonable documentation of the disability, the need for the service animal to accommodate that disability, and what work or task has the animal been trained to perform. As with all disability requests, you should engage in the interactive process with the employee to determine what is a reasonable accommodation and what alternatives are available.