Phelps at the Rio Games (Photo Credit: By Fernando Frazão/Agência Brasil [CC BY 3.0 via Wikimedia Commons)

When Michael Phelps announced his retirement at the 2016 Rio Olympics he really had no intention of swimming competitively again. However, that changed when the decorated athlete was approached by the Discovery Channel to help kick off Shark Week with a race against one of the world’s fastest and most efficient predators — a great white!

To prepare for the big event, Phelps, who has set 39 world records and garnered 28 Olympic medals, practiced by racing against a reef and a hammerhead shark – both computer generated, of course. While the swimmer’s time of 18.7 seconds was enough to beat the reef shark by 0.2 seconds, he fell behind the hammerhead, which completed the 50-meter distance in 15.1 seconds.

Great white lured with fake seal to estimate its speed (Photo Credit Discovery Channel)

On Sunday, July 23 at 7:00 p.m. ET/PT, over five million viewers tuned in to watch the highly anticipated Phelps vs. Shark: Great Gold vs. Great White. To compete effectively against the ferocious fish that can swim at speeds of up to 25 mph, or about five times faster than humans, Phelps wore a custom wetsuit. It was not only designed to reduce drag, but also featured a fin to mimic the shark’s powerful tail.

While television viewers saw the competitors swimming side by side, in reality, Phelps raced by himself in the cold Atlantic waters off of Cape Town, South Africa. The Discovery Channel film crew then inserted his computer-generated opponent simulating a real shark’s speed, which was estimated by luring a great white with a fake seal over the same 100-meter stretch of the Atlantic.

Phelps vs. Shark (Photo Credit: Discovery Channel screen capture)

Though Phelps managed to complete the distance in an impressive 38.1 seconds, 9.41 seconds faster than his personal best of 47.51 seconds, he was no match for the great shark, which clocked 36.1 seconds. Like a true champion, the fish celebrated the victory by leaping out of the water. Phelps, meanwhile, took the loss in good humor, tweeting: “Rematch? Next time...warmer water.”

The swimmer later said, “Honestly, the first thought that went through my head when I saw the shark, there’s probably very little chance for me to beat him.”

Final Score (Photo Credit: Discovery Channel screen capture)

While some fans were disappointed that Phelps did not race a live shark in the ocean, staging that would have been dangerous for the swimmer. Besides, Discovery Channel’s aim in organizing the stunt was to generate excitement and interest in sharks. Given that it was the highest-rated Shark Week special in the program’s 29-year history, they sure succeeded.

This isn’t the first time a star athlete has competed against an animal. NFL wide receiver Dennis Northcutt once raced an ostrich, while Olympic 200-meters champion Shawn Crawford sprinted alongside a giraffe. Bryan Habana, a rugby player, went a step further and tried to take on the world’s fastest land animal – the cheetah. However, despite a 35-meter head start, he was unable to beat the wild cat that is capable of reaching speeds of up to 70 mph!

Resources: Guardian.co.uk, vox.com,businessinsider.com,bbc.com, vanityfair.com, independent.co.uk