Library of Cryptozoology

At the time of his terminal illness [Ralph] Wetzel was convinced there was a genuine possibility of a third species of Choloepus in this region [Brazil, Peru, Ecuador] of upper Amazonas distinct from C. didactylus and C. hoffmanni , but the puzzle was not resolved before his death.

It [Zabalo River region in the Cuyabeno Wildlife Reserve] is rumored to be home to several species "unknown to science," as the phrase has it, such as the ferocious "giant giant river otter," the "black-water tiger," and the "howler-monkey tiger," a marsupial with humanlike hands.