Phelps finishes after the white shark only 2 seconds.(Artwork: Distractify.com.)
According to experts, the loss of heat when swimming in cold water and the difference in swimming speed compared to sharks is the reason Phelps lost.
The water temperature when Phelps swam only 13 degrees C. White sharks are warm-blooded animals, so they can survive and swim quickly in cold water environments. They maintain the ability to heat through blood vessels arranged specifically called "convection heat exchange", preventing the heat generated from the contraction of muscle radiating into the surrounding water. White sharks can swim at speeds of up to 40 km / h to catch sea creatures and other agile marine animals.
But humans are different, at such a cold temperature, our bodies will be shocked. Phelps said: " I only wear a thin swimsuit so it feels really cold. The biggest challenge for me is to try to keep the heat, which is extremely difficult when the water temperature is only 13 degrees. C. "
In the 100m race in South African waters, Phelps did not swim directly with a real white shark that raced with the CGI shark (technology that simulates computer images).