Not laboratory animals but pet therapy animals. 

This is Nelson Mandella - no, that's really his name. 

He's a schnoodle - part schnauzer, part poodle - going to work. 

He visits Castle Medical Center several times a week to cheer up the patients.

This morning, he's going to visit Dorothy who is recovering from surgery.

"At Castle Medical Center, we definitely support pet therapy.  Studies have shown that it's a great way to have the patient recover.  Some of things that it helps, decrease the anxiety level,” said Robin Pacson, nursing director at Castle Medical Center.

And that's just a start. 

Studies have shown a drop in blood pressure, heart rate and other positive signs of recovery.

Nelson is a trained pet therapy dog, allowed in the hospital.  But many patients have pets of their own waiting at home.

"It encourages them to want to get better so that they go home and are able to be reunited with their pets,” said Pacson.

Dorothy and Nelson obviously bonded and Robin Pacson says that is a clear sign of the patient's attitude.

"We definitely see the change in their emotions, from signs of despair to almost happiness, excitement.  It brings back memories of a time when they had their pets perhaps in childhood,” said Pacson.

Nelson's trainer, Donna Goo, claims she is just an interpreter for the dog. 

The fact is that it takes a special kind of dog - and person - to do this.

"It just takes a lot of patience.  And it takes a dog wanting to do this, being willing to do this, can't force a dog to do it.  A good temperament,” said Donna Goo, pet therapist.

If there is a specialist dog, it's Nelson.

"He actually is pretty good with patients that are suffering with dementia, Alzheimers, that they're confused,” said Goo.  “But it's interesting that they always know - dog."