how a duck body is dry always?

 

      Yet a duck spends most of its life swimming in ponds it is dry . The feathers do not account for this, for the duck's feathers are not different from the other birds. The secret of it is that the duck's feathers are oiled. There is an oil-making gland on the duck's back near the tail. The duck spreads a film of this oil all over the surface of its feathers. Now oil and water will not mix, so the water cannot get through this oil to wet the duck's feathers. Besides, the oil slips past the water, making swimming easier.