An ocean whirlpool is a rare phenomenon, with only five major whirlpools found worldwide. One of these giant water vortices is the Old Sow located near the Moose Island in Eastport, Maine.

Old Sow is the largest tidal whirlpool in the Western Hemisphere. It measures about 250 feet in diameter. It is caused by tidal activities between the Passamaquoddy Bay and Bay of Fundy. This water movements and the unusual topography of the sea floor create this swirling funnel of water.

The name ?Old Sow? is believed to have been derived from the pig-like noises created by the whirlpool?s movements. Other claim says that the ?sow? came from the word ?sough? (pronounced as ?suff?), which means drain. The mispronunciation of the word might have led to the whirlpool?s present name.