It's a moment neither whale nor human are likely to forget.

Photographer and dive operator Rainer Schimpf was recently documenting a sardine run off the coast of South Africa when he almost became part of the food chain.

"I was trying to get a shot of a shark going through the bait ball," Schimpf recalled in a video, "... the next moment, it got dark and I felt some pressure on my hip."

Based on the kind of pressure, Schimpf says he instantly knew that a whale had grabbed him. As shown in the dramatic footage below, the giant Bryde's whale got nearly all of the diver into its mouth.

"There is not time for fear in a situation like that," he said. "You have to use your instincts."

Fearful that the whale would dive and release him well below the surface, Schimpf says he took a deep breath and waited.

"The next moment I felt the whale was turning either way, and the pressure was released, and I was washed out of the mouth," he said. "I came back up onto the surface where surely I wasn't looking too clever."

Case of mistaken identity

Sardine runs like the kind Schimpf was documenting are a frenzied confluence of various species — gannets, penguins, seals, dolphins, whales and sharks, all working together to round up prey into massive bait balls. When massive marine species like the Bryde's whale, which average nearly 45 feet in length, soar through the middle of these corralled sardines, anything in their path can accidentally get scooped up.

"As they come up with their mouths open, they can't see what is in front of them, and I guess the whale thought it was a dolphin," diver Claudia Weber-Gebert said. "Whales are not man-eaters. This was no attack, it was not the fault of the whale, and they are really sensitive. They are gentle giants, and it was just an accident."

Four years ago, as shown in the video below, a videographer documenting the same sardine run was also almost inadvertently swallowed by a Bryde's whale.

Schimpf says getting that close to a whale isn't necessarily something he would recommend.

"It was an interesting experience for me, but surely nothing I want to do again," he said. "I don't think I had 'a whale of a time.' I now have an inside knowledge of a whale which nobody else has."

Michael d'Estries ( @michaeldestries ) covers science, technology, art, and the beautiful, unusual corners of our incredible world.

Diver makes lucky escape after whale nearly swallows him whole
A South African photographer gets the ultimate close-up after a mammoth Bryde's whale mistakes him for a meal.