With lethargic grace, the hammerhead shark slices through the blue gloom. It flicks its T-shaped head this way and that, surveying its underwater domain with the surety of knowing that the food chain comes to an abrupt end in its mouth.
The shark cruises 20 feet beneath me as I snorkel through the turbulent waters surrounding the Pacific islet of Malpelo, a Colombian wildlife sanctuary and gem for scuba divers.
"Widely recognized as one of the top diving sites in the world, due to the presence of steep walls and caves of outstanding natural beauty," the United Nations said in declaring Malpelo a World Heritage site this year in an effort to safeguard its thriving ecosystem.
The rocky islet lies 320 miles across empty ocean from Colombia's Pacific coast. Rising vertically out of the water, it reaches a height of 1,230 feet, while underwater it plunges more than two miles to the ocean bottom.
In truth, the term "island" may be too generous for a rock of less than a square mile. With powerful waves smashing the shore and the barren face picked clean of vegetation by legions of crabs, it's not surprising that some unknown sailor nicknamed it "Malveolus," Latin for inhospitable.
The first recorded reference to the island came from the Spanish conquistador Pedro de Cieza de Leon, who noted in 1542 that sailors called the rock Malpelo. In search of gold and colonies, Cieza de Leon saw little reason to visit the forbidding island.
These days, ornithologists delight in the island, which is home to 60 species of birds, including permanent residents and those who rest on it during continent-hopping migrations.
The 25,000-strong colony of Nazca boobies is the prize for bird-watchers. With black faces and black-tipped wings offsetting their snow-white bodies, the seagull-size birds virtually blanket the island, fearless of the few humans allowed to traipse through their home.
But Malpelo's star attraction is offshore -- the more than 600 hammerhead sharks and thousands of silky sharks that circle the rock.
As I sat on the side of a small launch preparing to plunge in with snorkel for a quick dip with the sharks, I tried to focus on the experts' vigorous rejection of the popular mythology that places the hammerhead in the fearsome category of man-eating sharks.
The scalloped hammerhead that owns the waters of Malpelo, and can grow 14 feet long, prefers to snack on small fish.
"It's a very timid shark, it can easily be scared of divers," said Sandra Bessudo, who runs the private Malpelo Foundation and has been diving around the island for 17 years.
The chances of a shark attack, let alone a fatal one, are tiny, I was reminded by George Burgess, director of the International Shark Attack File, based at the University of Florida.
Over the past 46 years you were twice as likely to be struck by lightning than be the victim of a shark attack, according to Burgess' group. That's little comfort to someone like me, for whom the man-eating mythology chews reason to pieces.
With a final whispered, "This is the stupidest thing I've ever done," I gingerly slid into waters where hundreds of multicolored fish swam. Manta rays and dolphins passed regularly.
Within seconds I spotted my first shark 20 feet below. It cruised along the island's underwater rock face where small fish hover and sea urchins wave in the currents.
Although tourists are not permitted on the island itself, people can enjoy the waters just offshore. About 600 visited last year, the Malpelo Foundation says.
Last year, Colombia's government expanded the zone around the island where fishing is outlawed to a 25-mile radius, seeking to protect the flourishing sea life. As much as the shark is king of these waters, it is still losing elsewhere against man.
On the 30-hour voyage back to the mainland port of Buenaventura, the crew of the Colombian navy frigate that had taken us to Malpelo spotted a rickety fishing boat and drew alongside -- drug traffickers frequently hide their drugs in fishing boats.
Sailors from the warship found a number of shark fins on the 20-foot boat. The fins are sold for about $11 a pound -- and exported to Asia to be used in shark fin soup.
The Malpelo Foundation's Bessudo has been campaigning for a moratorium on shark fishing, worried that it is driving the creatures to extinction. But she said a moratorium was unlikely, given the fishing industry's strong opposition.
She showed a collection of photographs and video of live sharks being tossed overboard after their fins were cut from their bodies. The sharks desperately struggled to swim as they sank, blood streaming from their open wounds.
Jackson Murillo, one of those on the small boat, said he and his colleagues weren't fishing for sharks, but the fish got caught in the boat's nets.
"We're poor and if a shark is there, then we'll take it," Murillo said. "With all the commercial fishing boats that fish here, with their huge boats, every year it's harder to find fish."