I have always loved the ocean. Recently my wife and I received our PADI certification to scuba dive and had the pleasure of diving at Stuarts Cove in the Bahamas. During a dive at a wreck called “Ray of Hope,” we were surrounded by carribean reef sharks ranging in length from 4 to 10 feet. It was truly one of the most beautiful and powerful experiences our lives. Watching these magnificent creatures materialize in and out of our field of vision, effortlessly moving through the water, is a memory I will always treasure.
I guess that’s a rather long segway for discussion about an episode of Mythbusters during Discovery Channel’s Sharkweek. They explore the truth behind the myth “swimming in the ocean with a dog increases your likelihood of being attacked by a shark.”
After creating a robot dog to simulate swimming and barking, they employ the use of dog urine, anal secretion, and trace amounts of blood similar to the amount that would be in flea excrement on a dog. (Did you know that flea poop is actually digested blood?) They hoped to determine whether any of the above conditions could provoke shark interest in robo-pooch thereby increasing a human’s risk of being attacked.
After placing the simulated dog in waters teeming with carribean reef sharks, the experiment began. No significant increase in shark activity was noted with swimming, barking, or upon remote release of urine or anal secretion. With the introduction of trace amounts of blood, however…it only took seconds before the sharks picked up the blood trail and traced it back to it’s source. The sharks did not attack but more or less investigated the robotic dog.
I believe the conclusion reached by the team was “plausible” but not confirmed. With rare exception, humans (and dogs) are not on shark menus. However, all bets are off when it comes to excited and/or agressive sharks that are incited to feed. Even in these instances it is often a case of mistaken identity.
Regardless, the episode did give new meaning to the importance of flea control.

Wishing you a wonderful summer’s end and safe beachgoing with Fido,

Dr. Keith