Originally published on Fri February 8, 2013 1:50 pm
Before they end up filleted and sautéed on your dinner plate, salmon lead some pretty extraordinary, globe-trotting lives.
After hatching in a freshwater stream, young salmon make a break for the ocean, where they hang out for years, covering thousands of miles before deciding its time to settle down and lay eggs in their natal stream.
So how do these fish find their way back to their home river?
Some 66 million years ago, about 75 percent of species on Earth disappeared. It wasn't just dinosaurs but most large mammals, fish, birds and plankton. Scientists have known this for a long time just from looking at the fossil record. If you dig deep enough, you find lots of dinosaur bones. And then a few layers up, they're gone.
But scientists couldn't figure out exactly what had caused this phenomenon. Of course, there were lots of theories.
One of the oldest known workplace dangers is breathing in tiny bits of silica, which is basically sand. Even the ancient Greeks knew that stone cutters got sick from breathing in dust. And today, nearly 2 million American workers are exposed to silica dust in jobs ranging from construction to manufacturing.