In a stunning encounter, divers off the coast of British Columbia found themselves in the middle of a pod of Steller sea lions.

Male sea lions, or bulls, battle each other for space and access to females, and can go 40 days without food in order to maintain their position.

National Geographic wildlife documentarian Bertie Gregory had a similar encounter when he plunged in the water to observe sea lions in their natural habitat, in the waters off Vancouver Island.

First, one bull approached him, toothy mouth open, blowing bubbles.

Male sea lions “usually blow bubbles to say ‘I’m the boss,’” says Gregory, referring to this initial encounter.

“On the face of it, they’re a little threatening. After all, you’re surrounded by a group of big predators that can grow to 11 feet long and weigh 2,000 pounds!” he said in an email.

After their initial show of dominance, the curious critters got playful. Gregory thinks the sea lions began playing once they got used to him and his camera.

“Once you get used to it, they’re generally very friendly,” he said. “They like to bite you a lot to feel what you are, but it’s not aggressive.”

The U.S. Marine Mammal Protection Act forbids anyone from approaching a seal-sized marine mammal from a distance of 50 meters or more.

A similar regulation proposed in Canada in 2012 is still being deliberated.

The Canadian law, or “Marine Mammal Regulations,” is primarily aimed at hunters, and its only reference to approaching the animals in the wild is more vague.

According to Prohibitions, “No person shall disturb a marine mammal except when fishing for marine mammals under the authority of these Regulations.”

So as long as their aim was not to disturb the animals, the divers could legally approach them from a closer distance than they would have been able to in the U.S.

Why would the sea lions approach? Gregory says the sea lions are just surveying their territory. “Basically, it’s very normal behavior with Steller sea lions around their haul-out spots,” he explained.

“They use these rocks to rest between fishing trips, so when in the water, they’re just relaxing and socializing. As a result, when you put a diver in the mix, they come and check you out.”

It was likely a similar situation when the divers in the recent video encountered the sea lions, Gregory affirmed.

“I actually just did another set of dives with that same group of sea lions for a different National Geographic project. Exactly the same thing happened!”

While not actually unusual for the area, the experience was unbelievable. The diver in the recent video enthusiastically told the videographer he was doing great, giving an excited OK signal underwater.

Gregory, who spends his life with interesting animals, was no less enthusiastic.

Their friendliness makes swimming with sea lions “like hanging out with a group of giant underwater dogs,” he says.

“It doesn’t feel like they’re being aggressive.”

Their lack of aggression and curiosity makes swimming with sea lions an “absolute magic.”