There have been a lot of alleged documentations of discoveries of giant human-like remains in eastern North America, and throughout the world. I certainly wouldn't say that I'm positive they never existed.
Mongabay News: Giant otters, river sentinels, now listed as threatened migratory species
With evidence that the giant river otter is in an increasingly perilous state, delegates to the United Nations Convention on the Conservation of Migratory Species (CMS) listed it as an animal ...