Why ducks float: a frank discussion

Intellectual conversation at Princeton can take some truly odd turns.

A few days ago at brunch, one of my friends was ribbing another for his vegetarianism. The attacker called on the Bible to strengthen his position, citing the dominion God granted Adam over "every living thing that moves upon the earth" as unquestionable evidence that animals are meant for consumption (Gen 1.28). This sounded like a dangerously broad definition of dominion to me and I joined the fray, pointing out that power does not always imply the right to eat one's subordinate. Ever the attentive Sunday school student, I further added that human beings were not given explicit divine permission to eat animals until later in the book of Genesis, after the flood, when God tells Noah and his sons, "Every moving thing that lives shall be food for you" (Gen 9.3). I was satisfied with this response until my friend responded, very self-righteously, "What about the ducks?"

"The ducks?" I repeated dumbly.

"Yes, the ducks," he said. "Why did Noah save them? Weren't they a waste of space on the ark, if they could have floated out the flood?"

Ducks do float, but whether they could have performed this feat for forty days and forty nights seemed less certain. Members of the sub family Anatinae, ducks belong to the largest and most diverse grouping of waterfowl. In comparison to geese and swans, ducks have smaller bodies, shorter necks, narrower and more pointed wings and more rapid wing beats.

Species of ducks are found on every continent, with the exception of Antarctica: Mallard ducks all over the Northern hemisphere, Mandarin ducks in China and Japan, Maned geese in Australia, Comb ducks in Africa, Rosy-billed ducks in Brazil, Paraguay, Uruguay and Argentina. The winter range of the Red-crested duck runs from the southern Mediterranean to the Black and Caspian Seas, denying me the easy out that Noah couldn't have found any ducks to take on the ark, anyway.

Ducks are well adapted to allow them to stay afloat without using too much energy. Ducks' bones are hollow for buoyancy, and a thick layer of feathers that interlock to trap air increases this effect. This air cushion also provides insulation in cold water to conserve body heat. Ducks' webbed feet further decrease the amount of energy spent in swimming.

In addition, ducks have a special oil-producing gland beneath their tails, the uropygial gland. Preening spreads this oil over a duck's feathers, rendering them waterproof. This suggests that a duck that had the misfortune to swim through a floating patch of degreaser would lose its waterproofing oil and eventually drown. This environmental hazard was probably not a problem five thousand years ago in Mesopotamia, however, where the pollution was mainly spiritual.

One objection to the picture of a group of ducks floating along behind the ark — a "paddling" of ducks, a "skiff," a "raft," a "team" or a "dopping" of ducks, depending on the species; a "sord" on the ground, a "flock" only in flight — is food. Ducks, like all birds, are built for flight, an ability that takes its biological toll in the form of high energy demands. Ducks must thus eat much and often in order to fuel their fast metabolisms. Fish, tadpoles and frogs, and perhaps certain insects, might have been available during the flood, but weeds, grains, seeds, roots and stems would have been inaccessible. Also, ducks sleep at night on dry land — "sleep," because often one eye will be open and only one hemisphere of the duck's brain is at rest, depending upon the duck's position within the flock. Forty days and forty nights of sleep deprivation would be hard to withstand, even if ducks do nap on the water.

Though ducks do float, it was probably a smart bet to offer them a spot on the ark. Otherwise, how would we enjoy today such delicacies as Orange Duck, Christmas duck and the indescribable Peking Duck? Those of us who aren't vegetarians are grateful to Noah for not taking the chance that ducks would survive the flood swimming on their own. Emily Stolzenberg is a sophomore from Morgantown, W. Va. She can be reached at estolzen@princeton.edu.