engleză
Cranes have existed for 60 million years. They and their relatives the limpkins and trumpeters are fairly closely related members of the order, Gruiformes that also includes rails, gallinules, coots, and other marsh-adapted birds. The skeletal anatomy and external features of a Crane has some similarities with large number of differences with limpkins and trumpeters. The sex of a Crane cannot be distinguished visually by researchers because there is no difference in morphology between male and female. A female-specific DNA fragment was cloned from female whooping Cranes(Grus americana). The Cranes of the world can be identified from the varying patterns of red, grey, black and white on their heads annd body structure and colour.Cranes perform a variety of behaviour patterns throughout their lives that have evolved to fulfil diverse functions. Mean sperm head length which did not vary significantly over weeks was found to be significantly over weeks was found to be significantly correlated with fertility (P0.04;r= 0.54; n =14). The populations of migratory Cranes are going to decline due to over hunting and destruction of their natural habitats.
