The Reality of River Monsters

In a widely-seen video clip, biologist and extreme angler Jeremy Wade hooks and wrestles an 80-pound goliath tigerfish (Hydrocynus goliath) on Africa's Congo River. The toothy, scary-looking creature, while real, seems all the more terrifying when shot with a fisheye lens and accompanied by a pounding, dramatic musical score as part of the new Animal Planet show "River Monsters."

Tantalizing tales of fierce aquatic killers have been the fodder of many documentaries, Hollywood thrillers and real-life narratives. But what's real and what's myth?

Piranhas are perhaps the world's best-known river killers, due largely to horror films like "Piranha" (1978), "Mega Piranha" (2010), and the upcoming "Piranha 3-D" (due out in August). Most of us have seen footage of these frenzied killers, their sharp triangular teeth ferociously efficient at ripping flesh.

While piranhas have a fearsome reputation and can be dangerous, piranha attacks on humans are very rare. Piranha will happily scavenge on a mortally wounded animal, though there are few if any confirmed reports of humans being killed by them. (Dogs and bees kill more people than piranha do.)

A relative of the piranha, the Megapiranha, grew to 3-feet-long (1 meter), or four times the size of today's piranhas. Scientists aren't sure why the fish-beast had seven teeth arranged in a zig-zag row, while today's piranhas sport six teeth. Fortunately the mega creature is not much of a threat, having died out several million years ago.

via The Reality of River Monsters | LiveScience.