Not all know, but the proverb which is often used in turns of speech "Like water off a duck's back" has a basis quite real facts connected with natural properties of plumage of this bird. Goose fat is able to push away water, simply without allowing a goose to become wet.
Water, on surprising combination of circumstances, not only does not get under feathers of geese, but also gathers the large drops which are rolling down along a body of an animal. However, if to dip a bird at first into warm, and then cold water, plumage loses the mysterious properties, it suggests an idea of existence of the certain lubricant which is not allowing water to get through strong "armor" from feathers, molecules of water and fat are not capable to interact habitually.
It is curious that geese worse than females dive and swim, they carry out the most part of the life on the land.
Fat secret
The special layer of fat covers skin and all mezhperyevy space of a bird, Fat is produced by glands which are located in the tail of a bird over a backbone, it is so-called secretion of coccygeal gland. A secret comes to light through special tubules when the bird presses on them a beak. By the way, a secret possesses rather unpleasant smell which is familiar to all who at least once plucked a goose.
Sometimes it is possible to observe how geese make the amusing actions by a beak similar to strokings, at this moment the bird independently covers plumage with the above substance creating the dense fat layer interfering soaking of feathers at contact with a water surface. Feathers in itself have no similar hydrophobic properties.
Protective properties of fatSecret also allows to make goose plumage more elastic and less fragile thanks to fats, wax and glycerides which are contained in it, and under the influence of the sun also turns into vitamin D so necessary for an organism of a bird thanks to substance to a 7-degidrokholistirol which geese absorb during daily procedures. Thus, at the sufficient level of light of a bird are capable to synthesize and provide the organism with an important element independently. It is interesting that the nature awarded with this property also many other birds belonging to the category natatorial, it allows ducks and geese to keep and ply so surely on water, and here herons and cormorants cannot brag of so effective work of gland.
At ostriches, some species of parrots, pigeons similar gland is absent at all.
Fat properties of a goose secret are already adopted by mankind and is used in the textile industry other modern industries.