I'm guessing it was a cultural thing.
The story that goes with the video is at this link:
http://preview.tinyurl.com/74u3n5a
Google Translate provided this English version:
Images from a group of 30 dolphins saving swimmers on a beach in Rio
de Janeiro, Brazil, has become a true Internet sensation.
Apparently mammals were swept by strong ocean current to the edge of
the beach Arraial do Cabo. Initially tourists were left contemplating
the disastrous scene, not knowing exactly what to do, until the Coast
Guard gave the example.
Delayed about two or three minutes in the 30 animals return to the
sea. The video shows tourists and Coast Guard took them by the tail
and pushing them into the water.
Eventually all the dolphins were saved, and what could have been a
tragedy became a clear example of love for animals.
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This is the first time I've tried Google Translate. It's flawed but
far better than I could have done. I wouldn't have written that the
dolphins saved the swimmers though. ;)