The video shows the young shark launching head-first in to the cage and wrapping its jaws around a bar, thrusting its nose near a man inside the cage.
Reilly said in a Reddit post the men in the cage were attempting to bait sharks into swimming alongside the cage, but the murky waters led to the juvenile great white swimming at the cage head-on while a person on the boat was moving the bait fish from one end of the cage to the other.
"The guy stands at the back or front of the boat and pulls the bait alongside the cage so the shark won't swim towards the cage but instead alongside it," Reilly said. "In this instance he threw the bait out and then the shark came speeding towards it. The boat moves [because] were in the [expletive] ocean so the guy was relocating from back to front and then saw the shark coming so he yanked the bait because they don't want to feed the shark."
Reilly said the red bar targeted by the shark is where divers usually put their hands.
"If you watch it in slow motion, the red bar in the cage is where you are supposed to put your hands.The [shark's] top jaw hit this location. If hands did not get moved, they would have been cut," he wrote.
The shark's lunge was caught from a second angle by another driver's GoPro camera.
