The umbilical cord is used by mammals to deliver nutrients to their babies

Directly connected to the mother's blood supply,it funnels nutrients and oxygen straight into the calf's body via the umbilical cord,and also exports its waste.Placental mammals can spend far longer inside the womb than other mammals.Baby blue whales, for instance, spend almost a full year inside their mother.The placenta keeps the calf alive right up until its birth,when the umbilical cord breaks and the newborn's own respiratory,circulatory,and waste disposal systems take over.Measuring about 23 feet,a newborn calf is already able to swim.It will spend the next six months drinking 225 liters of its mothers thick, fatty milk per day.Meanwhile,