Mammal belly buttons!?

Question

Do all mammals have belly buttons, or just humans? I thought it was all of them, but never really thought about it. My friend just asked me, and I wanted to know from anybody with more knowledge than me.

Answer 1

It might not be obvious at first but even mammals have those. My dog has one, my cat had one too. As far as i know, animals that are born from its mother's womb have belly buttons. The only thing i'm not sure is if the egg laying mammals, such as platipuses, err... platipi have one...

Answer 2

Egg laying mammals don't because their young never had an umbilical cord attached to a placenta which is what the belly button is