MONSTER FISH : http://news.nationalgeographic.com/news/2009/02/photogalleries/monster-fish-congo-missions/index.html "Evolution on Steroids" > in Congo.
"What we're seeing here is kind of evolution on steroids," said team leader Melanie Stiassny, a fish biologist at the American Museum of Natural History. Stiassny, a member of the National Geographic Society's Conservation Trust, was among the marine and evolutionary biologists, hydrologists, and kayakers who conducted the exhaustive research in summer 2008.
The Congo's freshwater elephant fish, such as the one seen above, use their long snouts to sift through river bottom sediments for food--another example of the Congo as a hotbed of evolution.
The fast currents and raucous rapids of the lower river create physical barriers that smaller fish cannot cross, said fish biologist Melanie Stiassny, who led a 2008 expedition on the Congo. At some points, the river flows more than a million cubic feet (28,000 cubic meters) a second--enough to fill more than 800 Olympic-size swimming pools every minute.
Such barriers isolate fish populations, and over time they become more and more distinct from one another, eventually evolving into new species.
Why do these kinds of fish end up in the river for which they are most accomodated if not for evolution?