Not that we necessarily needed more proof of how special and intelligent these wonderful mammals are but:
"The young dolphin gives a quick flip of her head, and an undulating silver ring appears--as if by magic--in front of her. The ring is a solid, toroidal bubble two feet across--and yet it does not rise to the surface! It stands erect in the water like the rim of a magic mirror, or the doorway to an unseen dimension. For long seconds the dolphin regards its creation, from varying aspects and angles, with its vision and sonar. Seemingly making a judgement, the dolphin then quickly pulls a ..."
Go read the rest at Project Delphis.
Thanks for the find go to bird on the moon