Lake Nicaragua is the largest lake in Central America. With a surface area of 8,264 km2 (3,191 sq mi), Lake Nicaragua has a maximum depth of 26m (85 ft) and is home to more than 400 islands. The presence of sharks in the lake once led scientists to believe that there was an unusual endemic species of Bull Shark which were unique to the country and could tolerate freshwater (most marine sharks can only survive in seawater). However, in the late 1960s it was discovered that the sharks were able to travel upstream on the rapids of the San Juan River which connects Lake Nicaragua to the Caribbean Sea.
photo: Rudyologist / wikicommons