Steamed they're delicious, but when clam bites man it's a battle to the death.
Danger on the Half-shell
by A. Hyatt Verrill
From Coronet magazine 1945 October, digital capture November 2007 by Doug Frizzle
In the pearl industry you dive for fortunes, but it's the wise diver who knows that he may come up with misfortune, too. Beneath the surface of the sea there are real dangers. There are predatory beasts. There is man's perpetual companion, accident. And there are the clams.
The giant Tridacna clam is a deadly man-trap with a mind of its own. Almost perfectly camouflaged among the corals, it lies with its yard-long shells open and waiting for prey. A disturbance in its vicinity will bring a quarter of a ton of shell down on the intruder, holding him until he drowns of suffocation. Stories have been told of pearl divers who resorted to chopping away their own limbs to free themselves from the fatal grasp when help from the surface could not be summoned.
One day a diver in full equipment, whom we'll call "Shorty," was working along a Pacific coral reef toward a fine mass of pearl shells. Suddenly the coral gave way beneath him. The iron bar he had been using to chop away obstructions slipped out of his hands. A strong current lifted him and whirled him about.
In a moment he was flat on his back. A giant clam held his air hose and lifeline in its fatal grip. He was unable to signal his mates far above him on the surface, and the air in his helmet would last only eight minutes!
But the Kanaka who was tending Shorty from the diving boat was alert. When the life-line had jerked suddenly and ominously in his hands, he knew there was trouble. The giant clam flicked horribly through his mind. Seizing an axe, he plunged into the sea to do battle with the living vise.
At the bottom of the sea, the Kanaka found Shorty lying on top of a deadly Tridacna clam. Bubbles flowing from his helmet indicated that he was still breathing, but he knew he could not last much longer. The Kanaka worked fast and hard, chopping furiously at the stubborn cartilage of the mighty shell. At last he freed the hapless diver.
When they were safely back on deck and breathing easier, they were able to figure out what had saved Shorty's life. The current caused by the closing of the horrible jaws had washed Shorty out of harm's way. At the same time his iron bar had fallen between the shells, holding them open just far enough to save his lines from being severed. Shorty wiped his brow. He was the luckiest diver living—at the moment
—From the book Strange Sea Shells and Their Stories: L. C. Page & Co.