So my daughter is sitting on the floor with my Labrador today. She starts to pet the dog, and the dog rolls over for a belly rub. My daughter, in her 19-month old voice, says “belly” and points to the dog’s pink belly. She then lifts her shirt and points to her belly button and says “belly.” Smart kid.
Then it hits me. Do dogs have navels? I’ve never seen something even remotely close to one on my Lab, or any other dog for that matter. Do fetal dogs do the umbilical thing? I mean, otherwise, how would they exchange oxygen and waste(s) with mom. But, with so many in a litter, wouldn’t they get twisted around? There must be something, but I’ve never seen or thought about it before. What goes on with dogs, and where does the umbilical, if there is one, connect?
Yes. They’re there, they just don’t look like ours. It’s just a small scar, usually kind of oval-shaped. I work with cats and dogs and as a technician who preps them for surgery I see them all the time. The fur can be in the way unless you’ve got a short-haired dog with a nearly naked belly!
They definitely are born with umbilical cords. I’ve cut enough of them to know! They just get tied off with a piece of suture material (if it’s being done in a hospital). If they don’t get tied off, it’s not a big deal. If left to nature, the mother chews off the placenta (and sometimes eats it), and the dangling cord just dried up and falls off within a week. Leaving a tiny scar where the belly button would be.
The bitch is supposed to break the membrane, and sever the cord, nibbling it down to a small stump. One of our bitches had a slight hernia here, which you could push back in.
They don’t get tangled for the simple reason that pups aren’t floating free in the womb. They each have a separate placenta, attached to the womb a bit like peas in a pod.
Here’s a picture of my American Hairless Terrier (Smudge)'s belly, with features labeled. His navel is a slight outie, and only noticeable when his skin is relaxed a bit.
Yes, they just don’t look like ours. My oldest dog has no visible mark in the skin but there is a hole in her muscles - she’s always had a small umbilical hernia.
All mammals have umbilical cords.
A dog’s uterus is ‘horned’ or bicornate- it’s a long Y rather than a squat pear-shape like ours, and the litter grows one by one down the length of the horns and are birthed in order. All mammals who commonly give birth to multiples have either bicornate, bipartite, or duplex uteri - long and narrower to keep multiple fetuses out of each other’s way. We have simplex uteruses, like monkeys and horses. Very much not designed for multiple births, hence all the problems.
With your assistance, Halligan’s navel was located after a very, very brief search. Right at the northern end of her belly/fur line, just a small, lighter-pink patch about a half-inch long.
So non-placental mammals don’t have an umbilical cord (or something very similar for the purposes of this discussion)? How does the embryo receive nutrition?
Birds have umbilical cords (basically) connecting them to the nutrition in the yolk. They also have navels.
Marsupials actually do have aplacenta of sorts, but different from that of placentals. It is formed from the yolk sac, rather than from other fetal membranes as in placentals, and does not persist for very long. Since the placenta is connected to the embryo by an umbilicus, even marsupials have navels.
