How Do Ducks Float?

logged findings of them for at least twenty years. The last report I know of is from August of twenty thirteen. They've ridden ocean currents up the eastern coast of the United States, along the shores of Greenland, and through the ice pack in the Arctic Ocean. Some two thousand are still unaccounted for. How these simple bathtub toys remained afloat for so long isn't much of a mystery. After all, they're made of lightweight rubber and filled with air. It's

no wonder the dense sea water holds them up. But how do their flesh and blood brethren accomplish the same task. Real ducks aren't made of plastic, and they contain more than just air. Today, let's talk about how ducks float. To understand this, you first have to understand why anything floats. Objects either float or sink in water because of what's called buoyancy. When an object placed in water weighs less than the amount of water that it displaces, the object floats.

If it weighs more, the object sinks. If that cargo ship had been transporting bowling balls, you can bet they wouldn't be cruising the high seas. Rubber ducks, however, are a different story. They typically weigh no more than say, zero point two ounces, but they take up about four point five cubic inches of space. For our metric friends,

that's about five grams and seventy five cubic centimeters. So that means that the water that they displace weighs over two and a half ounces or seventy five grams, so that water significantly outweighs them. Therefore, the heavier sea water will keep them afloat. Real ducks are also lighter than the water they displace, but it takes several things working in tandem to achieve that lightness. First up, ducks have a special gland called the europhygeal gland, or the prene gland.

This gland, located at the base of their tail, produces an oil that the ducks spread over their bodies to make their feathers water repellent. If you've ever seen ducks preening themselves and seeming to pay special attention to their tail feathers, that's why they keep going back to that gland for more oil. Because the oil treated feathers resist getting saturated with water, the birds weigh less than they

would if their feathers absorbed that water. This is also how the phrase like water off a duck came about. In addition to their water proofing abilities, duck feathers possess another quality that helps them to float. They trap air. The bird's feathers are tightly interlocked with a system of bendy barbs that hold air in. You know those little wings that kids wear on their arms in the pool to help them swim. Ducks practically have those built into

their feathers. If they need to dive under water for a quick snack, they just squeeze the air out by pressing their feathers in. The feathers will trap air again soon after the duck resurfaces and shakes any beads of water off of its oil treated feathers. Ducks further have a system of internal air sacks that helps to keep

them buoyant. These sects, which include the duck's lungs and are located along the length of the duck's body, are the equivalent of having miniature helium balloons inside of them. The secs stay filled with air unless the duck wants to dive underwater, at which point it squeezes the air out. However, one feature that does not help ducks float is the

weight of their hollow bones. Most birds that fly and some that don't, and some dinosaurs have a bone structure that's webbed through with pockets on the inside instead of being relatively solid, which most human bones are. If you think of it in terms of candy, the cross section of hollow bird bones is sort of like honeycombed toffee, and many human bones are more like a chocolate bar with a few crunchies in it and some kind of

chewy center, sort of. People used to think that the air pockets in birds hollow bones made them lighter, but it turns out that it doesn't because of that webbed or honeycomb structure. Birds bones are actually more dense than mammal bones. They have to be because they have to be stiffer and stronger so that they don't break the real benefit of these hollow bones is that they're essentially

part of the bird's lung system. Air sacks from a bird's lungs form and attached to the hollows in its bones as the bird grows, so when the bird flies, it has extra space to take in oxygen. That means extra oxygen will find its way into the bird's blood,

which will give it extra energy for flight. I guess it's possible that when a bird with lots of hollow bones really breeds in it might give them an edge in floating, but it would only be for as long as the breath lasts, so not really useful overall, and ducks don't have that many hollow bones to begin with. Not all birds have the same number. Birds that spend a lot of time gliding or soaring have more, and birds like ducks that spend a lot of time diving

have fewer. Some diving birds like penguins, puffins, and loons, don't have any hollow bones at all, which indeed places them at odds with the rubber duckies that we discussed early, which are entirely hollow, by the way, if you would like to learn more about their journey. There's been a bunch of research published about these rubber ducks and what they mean for our oceans and the plastics that wind

up there. This includes at least two books. A one is called This Is a Long One Moby Duck, The True story of twenty eight eight hundred bath Toys lost at sea and of the Beachcomber's oceanographers, environmentalists and fools, including the author who went in search of them, and another called slightly more simply Flotsymmetrics and the Floating World. How one man's obsession with runaway sneakers and rubber ducks revolutionized ocean science. Today's episode is based on the article

how do Ducks Float? On HowStuffWorks dot Com written by Jennifer Horton. Brain Stuff is production of by Heart Radio in partnership with how Stuffworks dot Com and is produced by Tyler Klais. Four more podcasts my Heart Radio, visit the iHeartRadio app, Apple Podcasts, or wherever you listen to your favorite shows.