A video of a diver appearing to high-five a shark made the rounds Wednesday (June 10) and one might reasonably ask whether that isn't a seriously dangerous thing to do. According to shark experts, it's not as crazy as it looks.
"Coming out of the cage like that is not as risky as it might seem," Carl Meyer of the Hawaii Institute of Marine Biology told Live Science. Meyer studies sharks as part of his work on coral reefs.
In the video, Joel Ibarra, a dive master on an expedition filmed for the Discovery Channel, appears to exit a shark cage and touch the pectoral fin of a female great white nicknamed Deep Blue. Ibarra was not really purposely slapping the female great white shark on the fin. Rather, he was pushing Deep Blue away so she wouldn't get cut on his shark cage. [See Stunning Images of Great White Sharks]
And Ibarra did this carefully: "The diver waits until the head of the shark has gone past, then climbs out to touch the pectoral fin. At that point the shark can't turn and get the diver. The diver keeps watching the white shark and then ducks back into the cage."
The key point is that the diver isn't in open water, but rather near a cage and a boat. Sometimes divers will try riding the dorsal fins of sharks or swim alongside them. That's much more dangerous, and could be harmful to the marine predators. "In these latter cases the shark can get the diver, and the diver just assumes/hopes that they won't, much like Timothy Treadwell [a conservationist and author of a book about living among bears in Alaska] assumed a bear would never eat him."
The film's crew members, including fisheries biologist Greg Skomal of Massachusetts Marine Fisheries and the Massachusetts Shark Research Program,and Mauricio Hoyos Padilla, director of Pelagios-Kakunjá A.C., a nonprofit that focuses on sharks, are doing very real research, notes James Sulikowski, a professor of marine science at the University of New England. "I actually know Dr. Skomal quite well and respect his work," Sulikowski said.
The researchers attached an acoustic transponder to Deep Blue. The device allows an autonomous underwater vehicle (AUV) to follow the great white and record footage with its six cameras. The AUV, which followed the female shark for more than three hours that day, also collects temperature, depth and other data. [Diver's Scary Great White Shark Encounter Caught on Video]
The footage could reveal secrets of great white sharks. "We know very little about these apex predators," Sulikowski said.
In this case it's especially important because the shark in question is pregnant. It is known that sharks give live birth, but nobody has ever seen a great white do that. Nobody has seen great white sharks eat without humans around, either. "The camera might reveal when and where these important behaviors occur," Meyer said.
In fact, Hoyos Padilla has found that pregnant female great whites wait in these waters in November and December so they can ambush arriving elephant seals at depths of 330 feet (100 meters), he said.
Though "Jaws" promoted a picture of great white sharks as vicious man-eaters, in reality they are important apex predators that would rather go about their own business than come face-to-face with their biggest enemy — humans.
In 2000, humans killed 100 million sharks and in 2010 that number was 97 million, according to a report in a 2013 issue of the journal Marine Policy. Meanwhile, 72 unprovoked shark attacks, three of which were fatal, were recorded in 2014 by the International Shark Attack File, compiled by biologists at the University of Florida.
Even those attacks were likely not because the sharks were chasing after a human. Ralph Collier, founder of the Shark Research Committee, noted that often sharks aren't being aggressive, just checking things out — and that many attacks are just that. If the sharks were on the hunt, the victims wouldn't survive. He added that sharks are more agile than people think. "These animals even at that size are extremely fast. If that shark were in an agonistic display, say defending an area, and perceived the diver as a threat, it can turn on you."
Hoyos Padilla agreed about sharks' curiosity for human swimmers, noting that the animals are not trying to eat humans.
"I have been working with sharks for, say, 14 years, and I have been out of the cage with seven sharks at the same time," Hoyos Padilla told Live Science. "I have seen sharks a lot of times, white sharks in front of me. But I have never been in a situation that I considered that I was in danger. They can tell that you are not a seal."
Live Science's Jeanna Bryner contributed reporting to this article.