UCSB Science Line Do cats have belly buttons? If not, then how do their offspring get their nutrients? Answer 1:This is mysterious, isn't it? I have a1.5-week-old kitten that I'm fostering for thelocal humane society and I haven't noticed anybelly button on her or her two older fosterbrothers. But if I had seen these kittens whenthey were born, I would have seen the umbilicalcord.Kittens in the womb get their nutrients fromtheir mothers the same way we do, through anumbilical cord that's attached to the placenta onone end and the belly of the fetus on the other.All mammals have this system except for themarsupials (like kangaroos and opossums) and thetwo egg-laying mammals (platypus and echidna).Blood from the mother carries oxygen and nutrientsto the placenta and carries wastes away. Thecleaned, fueled, oxygen-rich blood then flowsthrough the fetus.So why are we the onlymammals (as far as I know) with visible bellybuttons? Basically, the answer is that the bellybutton heals more completely in kittens than inus, but why? Maybe it's because of how we tie offand cut the umbilical cords of babies. Most mammalmothers bite the cord between the baby and theplacenta, leaving a fairly long piece of the cord.Then the cord shrivels up over the next few daysand falls off. I wonder if we'd have belly buttonsif we did the same thing. Maybe it's becauseour skin is rather different than the thin skin ofmost mammals. Now I'm wondering if chimps havevisible belly buttons.Answer 2:What a great question! It never occurred to methat cats should have belly buttons. You see theattached bit of umbilical chord on newly-bornpuppies, so puppies must have them, but what aboutcats? Basically, all mammals that develop in aplacenta, attached to their mother with anumbilical chord, should have a belly button or atleast a scar where the umbilical chord attached.(There IS a group of mammals that do not developin placentas, and thus do not have belly buttons.Can you think of an example? You won't find themin North America!) According to Cecil Adams, theguy who answers questions for "The Straight Dope"column (http://www.straightdope.com/), cats have ascar hidden under their fur just tail-wards oftheir rib cage where the umbilical chord attached.This is the cat equivalent of a belly button.Answer 3:Cats do have umbilical cords (which is how theyget nutrients), and normally the mother cat seversit with her teeth, and the belly button will notappear as humans do - the mother cat does not tiea neat knot!!!Click Here to return to the search form. Copyright © 2015 The Regents of the University of California, All Rights Reserved.UCSB Terms of Use
