How Polynesians Traverse the Ocean

I wrote about the new book I'm reading last Saturday. It's still really interesting. I just finished the part about surviving on the high seas and am currently reading about deserts. Dr. Kamler talks about how Polynesians were able to traverse the open waters, going from island to island without seeing anything but water:

Not having the navigational capabilities of migratory birds or oceangoing fish, the Polynesians were nevertheless able to create an ecological niche for themselves by making astute use of the senses they did have. Crossing empty horizons, they learned to locate land by indirect clues. A greenish tint on the undersurface of a cloud was light reflecting island vegetation. Birds that roost on land could be followed home in the evening. Islands generate sounds when breakers crash against the shore and emit smells when wind carries the scents of flowers, fruit, and earth. Waves that strike an island bounce back and radiate outward, creating a ripple pattern that can be seen on the surface and felt against the boat.

 Isn't that so crazy? You can only see for about two miles until the earth bends away. Can you imagine smelling flowers and earth from two miles away? Your senses would have to be so honed to be able to pick that up. Also, on another note, did you know that a shark's nostrils are independent? It's kind of like our ears and how we can tell where a sound is coming from. A shark can smell a drop of blood that has been diluted over 10 million times and locate the direction it came from with frightening precision. I find myself thinking about a shark's sense of smell when I don't have to think about anything, like when I brush my teeth in the morning or eat breakfast. I wish I had that skill.