Do bats have belly buttons?
Bats are mammals, just like you and I. As a baby bat grows within its mother, it is fed with an umbilical cord, just like human babies. The belly button is where this cord was attached to the baby (just like you!). Your pet cat or dog also has a belly button!
Not all mammals have belly buttons. Placental (or eutherian) mammals have belly buttons. They nourish their fetuses by a placenta that is connected to the umbilical cord. Non-placental mammals do not have belly buttons - this group of mammals includes monotremes (metatherian mammals), which lay eggs, and marsupials (prototherian mammals), which nurture their young in a pouch.