Diving With Bullsharks | World's Biggest Bullshark

Neil and James search a shipwreck for the mega shark, Big Bull, and other large bull sharks that may be her descendants.

"I'm good over here," Neil says. Bull sharks have a pack-like mentality and swarm around possible food. They surround the divers.

Neil and James nestle into the wreck for protection. James uses two lasers, which work like an electronic ruler, to confirm the size of the bulls. "If one is close to 10 feet long, it could be Big Bull, possibly the largest shark alive."

Multiplying the six-inch long distance of the lasers, they estimate that this shark is young. From snout to the curve of the tail, it measures a little over five feet long.

But nearby, a giant pushing nine feet—only inches smaller than Big Bull—was recorded in 2012. They get more measurements. "Awesome!"

But the strong current, with this many sharks, turns this dive dangerous.

"This card is gonna carry me to England, by the way. How about that?"

"That was epic!"

"No, it's a bunch of some nice size bulls—not as big as Big Bull—but I feel really good about this."

"It's a good starting point to take your search to the next level."

They've confirmed bulls as large as those reported by local divers and fishermen. While they're not quite the size of Big Bull, this is her territory. If Neil's theory is right, the sharks here may be her offspring.