Physical description: Long neck like a swan’s, 
held high above the water.

Behavior: Nocturnal. Can travel on land.

Distribution: The lake region of Chubut 
Province, Argentina, including Lago Blanco; the 
adjacent region of Chile.

Significant sightings: The director of the 
Jardín Zoológico at Buenos Aires, Clemente 
Onelli, interviewed a farmer who lived on Lago 
Blanco in 1897 about strange, nocturnal noises 
heard along the lake’s pebbly shore. A longnecked 
animal could sometimes be seen on 
moonlit nights.

On October 18, 1921, prospector Martin 
Sheffield came across the tracks of a large animal 
west of Esquel, Argentina, and followed them to 
an unnamed mountain lake where he saw a plesiosaur- 
like animal swimming.

Onelli organized an expedition, led by José 
Cihagi and Emilio Frey, that set out to investigate 
these reports on March 23, 1922. On April 
18, despite some bureaucratic problems with 
permits, the group reached the lake where 
Sheffield had seen the animal but did not find 
anything (despite setting off some dynamite in 
the lake); the group was forced to return to 
Buenos Aires on April 26 before the southern 
winter set in.

Possible explanation: The Giant otter 
(Pteronura brasiliensis) is found much farther 
north, though there is a historical record of its 
existence from Uruguay. It grows to a length of 
6 feet, including the tail.

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