sleeping sperm whale
© Reinhard Dirscherl, CorbisA sperm whale swimming just under the surface in the Caribbean, Dominica.
Sperm whales, it is not widely known, have the largest heads in the animal kingdom. (At around six meters, (20 feet) long, a sperm whale's head constitutes roughly one-third of its entire length from tip to tail.) Sperm whales are also the deepest divers in the mammalian world, able to descend in excess of 3,000 meters (10,000 feet) in search of giant squid, subjecting themselves to pressures that would crush a human.

And, perhaps most unexpectedly of all, sperm whales also produce extraordinarily valuable poop.

Not all sperm whales produce this poop. And at least some - and perhaps most or even all - of those that do, die in the process. But the result is, to humans, little short of golden.

The poop in question is called ambergris, and it is the result of the sperm whale's digestive system doing battle with the remnants of the whale's squid prey. The squids' beaks remain undigested, and make their way through the intestines until, in about one percent of sperm whales, they congeal in an ever-growing mass of fecal matter, a large and immovable object that acts as a rectal dam until, in some cases, the whole thing is (presumably painfully) expelled, while in others it becomes so large that it ultimately proves fatal.

Whale ppop
© Christopher KempA piece of ambergris weighing almost two-and-a-half pounds in the Auckland War Memorial Museum collection.
Whether via the volition of the whale itself or as a result of scavengers ripping open the innards of the deceased cetacean, the mound of ambergris reaches the ocean. There, writes Christopher Kemp in Floating Gold: A Natural (& Unnatural) History of Ambergris, it may tarry for weeks, months, years or even decades until, perhaps, eventually it finds its way ashore, either as one weathered lump or as an abundance of smaller pieces.

Particularly in the latter case, it may pass unnoticed visually among the debris, natural and artificial, that the tide has carried to land. What makes it stand out, however, is its smell. Kemp quotes writers and observers who variously compare the unique odor of ambergris to fine tobacco, the wood in old churches, sandalwood, fresh earth, fresh seaweed, cow dung, Brazil nuts, newly-mowed hay, and the "faintest possible perfume of the violet."

It is that unique and hard-to-define smell that makes ambergris, as Herman Melville in "Moby Dick" described it, "worth a gold guinea an ounce to any druggist." For it is, among other things, a highly sought-after - and, despite the best efforts of chemists, not perfectly replicable - component of perfumes. Writes Kemp:
(Ambergris) is sold by the gram in little pebble-size pieces to independent perfumers or in bulk to those who can afford it. It is peddled in the dusty souks by herbalists in Morocco and Cairo, where it is an aphrodisiac and stirred by the teaspoon into cups of sweetened tea. Across the Middle east, it is used as incense in religious ceremonies. In China, it is eaten. Throughout history, it has been used as a medicine, as an ingredient in cooking, a component in fragrances, an adornment, a sign of wealth, an acknowledgment and celebration of the great dark unseen mystery of the ocean.
Whale tail
© Christopher Swann, CorbisA sperm whale tail in the Gulf of California.
Once, when sperm whales were slaughtered for commercial gain, ambergris was in relatively plentiful supply. Now, the sole source is those portions that make it to shore and are found by beachcombers with a keen eye (or nose), many of whom stake out territories that they scour repeatedly, hoping to make a find that they can sell to a hugely competitive and secretive trading network.

So on this World Oceans Day, take a walk to the coast, and stroll along the shore. Look out over the rolling waves, and contemplate the enormity of what lies beyond and the abundance of life that lives therein. And look down at your feet, at the detritus that marks the boundary of land and sea. Look closely, and if you see something unusual, pick it up. Lift it to your nose and take a deep breath. If it smells of old churches - or Brazil nuts, or hay - then the chances are that it is sperm whale poop. And it may be worth its weight in gold.