Nature and climate News | Scientific ecology

Caviar visited the duck’s stomach and fry hatched from it

An amazing journey of the eggs

An amazing process was observed by the biologists of the Center for Environmental Research in Debrecen, Hungary. It turns out that fish roe can withstand fantastic loads. Once in the stomach of a mallard duck, carp eggs have come a long and dangerous way in the bird's body. And then, being in the open space after the bowel movements of the duck, the eggs remained viable.

The scientists believe that studying that unusual journey of the eggs more detailed, they will be able to develop a mechanism for the spread of invasive fish. Mallard ducks were under the supervision of the specialists in the laboratory.


They were fed different kinds of food, and in the diet they came across carp caviar. From the moment the eggs were in the body of the bird, a long journey began for them, which involved the conversion of the eggs into a nutrient base. However, a new study helped to find out that the eggs that had been excreted by the ducks retained their viability.

For many years, science has wondered how to populate isolated bodies of water with certain types of fish. Patricia Burkhardt-Holm from the University of Basel in Switzerland believes that the duck experiment answers that question.

It has been known that birds are able to distribute plant seeds using their own feathers, transfer seeds on limbs, or in excrement. But science has never considered the option of birds transferring viable fish eggs. No one expected potential fry to survive in the intestines of the duck.


In Vinc's laboratory, biologists fed eight ducks with carp caviar. In total, the birds ate about a thousand eggs. It is about 0.2% of the eggs swallowed by the mallards were viable after defecation. The scientists were shocked that some eggs contained active embryos.

And other eggs testified that the fry have already hatched. The researchers have calculated that migratory ducks can thus carry fish eggs over a distance of several tens of kilometers.