A service dog is considered a working animal, not a pet. Service dogs must meet exacting criteria in order to obtain service dog registration. A service dog is not the same as a therapy dog, who goes into hospital settings with a handler to bring comfort to patients. Rather, a service dog serves a definable function to aid her owner in living with a disability. Service dogs can help people who are vision or hearing impaired, suffer from seizures or have trouble moving, or are in a wheelchair. Service dogs can also assist people who suffer from PTSD, severe anxiety or depression.
While most service dogs are labs or retrievers, very large breeds like the Great Dane or Pyrenees can help people who need a lot of physical assistance, are very tall or who simply prefer the character of these breeds.