To answer a question myself, recently I've read that
Years and years ago, a long umbilical cord enabled a woman to grasp her baby after birth and run away from predators"
$Question:$ How umbilical cord is evolved and what's the reason behind it's elongation?
There is at least one position that supports this claim:
So why 61 cm? Umbilical cords of whales, porpoises, goats and other mammals are rela- tively shorter than the human cord. Walker and Rye of Cambridge surmised in the British Medical Journal in 1960 that prehistoric humans evolved length for protection. Nature's purpose was to allow the mother to pick up the newborn without disturbing the placenta. The event of breast feeding would then separate the placenta - an event which could attract predators. Having the fetus in tow would allow escape for mother and child.
(title: Silent Risk, auth.:Jason H. Collins). Well, right now I feel confused a bit...