A great white shark. Credit: Skeeze, Pixababy.
It’s a scary thought, but does the claim stand up under scientific scrutiny? Just know that no shark is darting for your swim trunks from miles away. Sharks have highly developed brain regions for sensing odors. They can pick up 1 part of blood per 10 billion parts of water. But while this might conjure up the image of a shark honing in from miles away, it’s useful to know what 1 in 10 billion parts of water actually is. A good way to visualize this is the ball of a ball-point pen in an Olympic swimming pool (still impressive nevertheless). Molecules, of course, scatter and drift in the water and there are loads of them in the ocean. The best a shark could do is pick up blood from a couple of football fields away if the currents and other conditions are just right.
7. Humans evolved from chimps
A chimpanzee in the Leipzig Zoo. Credit: Thomas Lersch, Wikipedia Commons.
While the chimpanzee may be our closest living relative (homo sapiens are equidistant from them and bonobos), we didn’t evolve from them per se. Rather, chimps, gorillas, and humans share a common ancestor that walked the Earth some 6-10 million years ago. A recently unearthed fossil from Kenya’s Rift Valley may be the common thread. This has tentatively been identified as the Nakali ape (Nakalipithecus nakayamai). So how closely related are we to chimps? We share 98.8% of the same genes.