Lake Nicaragua shark (Carcharinus nicaraguensis)

"HIDDEN DEMON OF THE PEACEFUL LAKE

"High in the jungles of Central America, Lake Nicaragua lies shimmering amid green hills in a setting of breath-taking beauty, inviting the passer-by to escape the oppressive heat in the coolness of its waters. But this can be an invitation to death, for under its calm surface lurks one of the world's few fresh water maneaters, the Lake Nicaragua shark. Averaging 8 to 10 feet in length and closely related to the Atlantic ground shark which rarely attacks men, this predator was originally a sea-dweller who migrated up the San Carlos River from the Caribbean. When prehistoric earthquakes cut off its return route to the sea with waterfalls and rapids, this shark settled down in its present home and somehow acquired a taste for people. The Lake Nicaragua shark is a deadly menace to swimmers in the lakeshore shallows because it hugs the bottom, so that no racing fin breaks the surface to warn of its approach. Local people and visitors alike have succumbed to its stealth, their first hint of danger being the mortal crush of the murderer's powerful jaws."

--Animal World in Color, Volume 8 - Hunters: Birds, Fish, and Amphibians, edited by Maurice Burton, Childrens Press: Chicago, 1969