This profound question elicited a wide range of replies from readers of New Scientist , some of which are worth recording here. W. Smith supposed that because the flamingo has exceptionally long, thin legs that it was difficult for its heart to return blood from its feet. Therefore, by standing on one leg and occasionally switching, the flamingo prevents blood from collecting in its feet.
Flamingos roost upon one of their legs while the other half of their body is in the sleep stage.
When the other half of their brain and body earns a rest, they change legs. A leg that is in the sleep stage would not support the bird as a whole. So ducks only bump into them half the time. William R. Corliss Other Sites of Interest SIS . Catastrophism, archaeoastronomy, ancient history, mythology and astronomy.