Most animals chew it off. I can see prehistoric man doing the same, or using some kind of knife to cut it.
The placenta, where the umbilical cord attaches to the mother, is delivered very shortly after the baby is (think immediately after), so it wasn’t like the babies were attached to the mother for a long time.
Well, there is a thing called a lotus birth where the afterbirth is carried in a small bag whilst still attached to the baby. It simply dries and falls off.
My daughter was born naturally and her umbilical stump took 3 days to fall off.
My son was born via c-section and his umbilical stump took 12 days to fall off.
My midwife said that it took longer for his umbilical stump to fall off as he wasnt born vaginally and didnt come into contact with vaginal bacteria…
Edit – just because i have been messaged a few times. i did not have a lotus birth for either. Their cords were cut in the hospital and fell off later at home.