The Physics of Great White Sharks Leaping Out of the Water to Catch Seals
Do you know what is indisputably awesome, even for those language-sticklers who claim you can only use awesome "in its original sense"? Great white sharks jumping out of the water to eat seals.
While you or I might have been content to just watch the Planet Earth episode about this phenomenon, biophysicists tried to describe the physics of a shark launching itself at a seal in a November 30 paper in the journal Marine Biology Research.
They dropped decoy seals into the water to elicit 121 Great White strikes over a period of years. Using the data of how high the sharks jumped, they were able to calculate how fast they were moving.
"For example, on 18 June 2002, broadside to our observation vessel, a 3.5-m white shark performed a breach with a height of [at least] 2.4 m, a water-escape trajectory of [plus or minus]45 degrees, and duration of 1.2 s," they write. That is to say, an 11.5-foot shark jumped 8 feet out of the water and caught air for more than a second. Doing the math, they estimate that the sharks get up to speeds of almost 10 meters a second (or greater than 21 miles per hour)!
Most shark attacks on the seals occurred where the bottom depth of the water was 26-30 meters. In those circumstances, the researchers calculated that the sharks would reach the seals in around 2, 2.5 seconds after they begin their strikes. That's not much time for a seal to get out of the way, which is one reason that shark attacks are successful from between 40 and 55 percent of the time, depending on the lighting conditions.