Not everyone knows, but the proverb “Like water off a duck”, often used in speech, is based on quite real facts related to the natural properties of the plumage of this bird. Goose fat is able to repel water, just not letting the goose get wet.
Water, by an amazing coincidence, not only does not penetrate under the feathers of geese, but also collects in large drops, rolling down the body of the animal. However, if you dip the bird first in warm and then cold water, the plumage loses its mysterious properties, this suggests the existence of some kind of lubricant that does not allow water to penetrate through the durable "armor" of feathers, because water and fat molecules are not able to interact as usual way.
It is curious that geese dive and swim worse than females, they spend most of their lives on land.
Bold secret
A special layer of fat covers the skin and the entire inter-feather space of the bird. Fat is produced by the glands located in the tail of the bird above the spine, this is the so-called secret of the coccygeal gland. The secret comes out through special tubules when the bird presses on them with its beak. By the way, the secret has a rather unpleasant smell, which is familiar to everyone who has plucked a goose at least once.
Sometimes you can observe how geese perform funny actions with their beak, similar to stroking, at this moment the bird independently covers the plumage with the above-described substance, which creates a dense fat layer that prevents feathers from getting wet when they come into contact with the water surface. Feathers by themselves do not have these hydrophobic properties.
Protective properties of fat
The secret also allows you to make the plumage of the goose more elastic and less brittle thanks to the fats, wax and glycerides contained in it, and under the influence of the sun it also turns into vitamin D much needed by the bird's body thanks to the substance 7-dehydrocholystyrene, which geese absorb during daily procedures. … Thus, with a sufficient level of light, birds are able to independently synthesize and provide their body with an important element.
It is interesting that nature has awarded this property to many other birds belonging to the category of waterfowl, because it is it that allows ducks and geese to stay so confidently and ply on the water, but herons and cormorants cannot boast of such an effective work of the gland.
In ostriches, some species of parrots, pigeons, such a gland is completely absent.
The fatty properties of goose secretions have already been adopted by mankind and are used in the textile industry in other modern industries.
