From the Mother Nature Network web site www.MNN.com 

The confusing world of service dogs
mnn.com

The term "service dog" is used a lot in public these days. What was once an assistance animal for blind or deaf individuals, highly trained service dogs are now helping people with a wide range of disabilities, acting as seizure alert dogs, PTSD service dogs, alerting a handler with diabetes to when his blood sugar dips, and so much more.
However, as an understanding of the broadened range of what a trained service animal can do reaches the general public, and with the important work the Americans with Disabilities Act (ADA) has done to increase public accessibility and privacy for people with service animals, it has become common for people to call their pets service animals even when they don't meet the legal definition.
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