This is an image cropped from a 1687 map. It is possible that it is an image of an extinct animal, but this would have to be determined by a scholar. I am contacting Yale about this.
Source
Hennepin, Amplissimae Regionali Mississipi (a map), 1687. From Yale University Library, Map Collection (ref. # 71, 1730 – copy 1).
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