But one fearless swimmer embraced the potentially fatal meeting with open arms, by tossing fish into the predator"s gaping jaws.
The moment was captured by underwater photographer Daniel Botelho at Tiger Beach in the Bahamas where visitors can feed the powerful animals by hand.
The 32-year-old said: "They look pretty scary when they open their mouths.
"You need to give the shark some space and let it know you are there before it arrives to grab the fish."
But the Brazilian warned the experience was not one for the faint-hearted.
"You need to have lots of respect, caution and be mentally focused throughout," he added.
Mr Botelho took to the water with seasoned divers Vincent and Debra Canabal to achieve the dramatic photographs.
Among them is an image of Mr Canabal feeding a four-metre long female Tiger shark called Emma.
Despite the huge risk involved with such dives, Mr Botelho claimed "shark tourism" is one of the few ways to preserve the species for future generations.
"The truth is that when 90 per cent of the tiger shark population is gone because of the finning market, tourism will be the only way that will keep sharks alive."
"I believe that tourism and feeding are not a problem if this is keeping sharks protected from the extinction."
Since 1972 it is thought the global Tiger shark population has fallen by 97 per cent due to the increase of shark finning.
Twenty species of shark are listed as endangered by the World Conservation Union as the demand for shark fin soup grows.
Tiger sharks are known to swallow anything that crosses their paths, feeding on a variety of fish, birds, seals and smaller sharks.
Open wide! Incredible underwater photos of a fearless diver hand-feeding a killer sharkOpen wide! Incredible underwater photos of a fearless diver hand-feeding a killer shark