12-year-old Leonardo de Souza is enjoying a special treat - he's swimming with rare Amazon pink river dolphins.

But the outing is not just for fun - these dolphins are thought by many to have healing effects for the mentally and physically handicapped.

Leo, as de Souza is known, was born without arms and with truncated legs.

He was always slow and quiet - but his mother Cleonice Araujo says since his dolphin therapy sessions, he's improved dramatically.

[Cleonic Araujo, Leonardo DeSouza's Mother]:
"He wouldn't play much; he didn't know how to walk very well. But now, he's changed. He plays ball and he talks to everyone."

The person behind the dolphin therapy is physiotherapist Igor Simoes.

He claims that the animals are compassionate and can help build a patient's self-confidence.

He also believes the sound waves emitted by the dolphins stimulate healing in kids like Leo.

[Igor Simoes, Physiotherapist]:
"Leo has greatly developed his balance and his psychomotor skills. Because of his condition he needs to have very good control of his spine to walk on uneven terrains. He has also worked a lot on his self-esteem."

And what does Leo think of the therapy?

[Leonardo de Souza, 12-Year-Old Handicapped Patient]:
"It helped me a lot in playing soccer, in swimming, in school, in everything."

But the practice is not without its critics. A recent U.S. study states there is no scientific evidence of the treatment helping to cure diseases and that it could also result in accidents.

The Brazilian government however, is supporting Simoes' research into dolphin therapy, as long as the mammals are free to come and go as they please.

For Simoes and his patient, there is no doubt that these rare dolphins truly are instruments of healing.