Have you ever wondered why your cat doesn’t have an innie or an outie belly button like you do? The answer is surprisingly simple, and cats are actually quite similar to humans in the way they grow and birth their babies.
To understand why cats don’t have the same type of belly button as a human, we need to understand how a belly button is created and why a belly button is there in the first place.
All cats technically have a belly button that is created the same way a human belly button is through the umbilical cord. Unlike a human, a cat’s belly button will not become an innie or an outie because of the way the umbilical cord dries and falls off the body.
A cat’s belly button is located halfway down their belly, measuring about 5mm in diameter, and it looks like a scar. The belly button is not easily seen because of the fur that covers the cat’s skin.
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Your belly button is also known as a navel or scientifically an umbilicus. The belly button is where all the blood vessels are attached from the mother to the baby before birth. This is the baby’s life support in the mother’s uterus. The umbilical cord supplies nutrients, oxygen and removes all the waste products for the baby.
Once the baby is born, it has to be separated from the mother so it can start living on its own. When the two are separated, the umbilical cord is cut, and the person or mammal is left with a tiny scar where the umbilical cord was attached.
For humans, this scar ends up looking like the belly button you are used to. That is because of the way the abdominal muscles form around the drying umbilical cord. There is lots of debate in the scientific community on why a human belly button forms the way it does, but there is no conclusive evidence that states the way the baby’s umbilical cord is clipped, cut, or handled has anything to do with the way it forms as they grow up.
How is a Belly Button Made
When the umbilical cord is cut, the small scar it leaves changes depending on how the body heals around the scar. For mammals like cats and dogs, the cord is simply cut and allowed to fall off in the first one to five days.
Once the cord falls off, it leaves a small slit-like scar on the animal that will produce a cowlick in the fur once the fur starts growing around it. It is possible to find your cat’s belly button, although difficult due to the hair and size.
The belly button can also be confused with a spay scar, which is in a similar area on the abdomen of your cat. The spay scar sometimes looks so similar to a belly button that some vets have started tattooing some cats to ensure that other vets can easily tell if they are spayed later in life. This has become especially important in stray cats and cats from adoption agencies.
In humans, the cord is usually clipped off by the doctor or attending. That cut, however, has no say in whether the belly button becomes an innie or an outie, and the way the scar heals is dependent on the baby’s body. Scientists have been unable to attribute the belly button’s growth to genetics or procedural decisions.
Outies are very uncommon in humans, so if you have one, consider yourself lucky. The estimates are that only 10% of the world population has an outie belly button. The interesting part is most doctors don’t believe they can control if a belly button is an innie or an outie. The way your belly button forms is up to how the umbilical cord falls off.
For an animal, if you see an outie belly button, it often means the animal has a small hernia because the abdominal wall did not close properly, and a small part of the animal’s insides are protruding. Most of these issues are an easy fix through a small surgical procedure.
The outie belly button on a cat or dog is better known as an umbilical hernia. Umbilical hernias are rare and happen more in puppies than they do in kittens. A small hernia will not cause any major issues, and if small enough, it is often left untreated.
What Animals Have a Belly Button
There are three different types of mammals: placental mammals, marsupials, and monotremes. Each type produces babies in a different way. While all placental mammals will technically have a belly button, most of them don’t show up looking the same as humans.
Marsupials are sack animals, and the babies are not connected to the mother for nutrients using an umbilical cord. The babies grow in a yolk-like sack then move up into the mother’s pouch to be fed by the mother for their first few weeks of life. No umbilical cord is attached to the baby if it is a marsupial. Common marsupials include the kangaroo, wallaby, and the opossum. Most marsupials are located in Australia and the Americas.
The monotremes only have two types of animals left in existence: the echidna and the platypus; these are the only mammals that lay eggs. The reason they are still considered mammals and not part of the bird or reptile family is because they still feed their babies milk after they hatch.
How Cats Give Birth
Similar to how humans give birth, cats grow kittens in a placenta within the mother’s stomach. A mother cat is also called a queen. The placenta attaches to the uterine wall, and the umbilical cord connects from the queen to the kittens.
The difference between cats and humans is that cats give birth to multiple kittens every time while a human will commonly only give birth to one baby. Each kitten has its own placenta and umbilical cord. The only time this is different is when a cat has identical twins. The twin kittens will share a placenta but still have their own umbilical cord for nutrients that attaches to the queen.
Once the kitten is born and takes its first breath, the queen will bite or lick the cord until it detaches. It is common for cats to eat the kitten’s placenta to keep the nutrients.
Finding Your Cat’s Belly Button
Finding your cat’s belly button can be difficult even for a vet. There are a few reasons for this.
- Cats’ scar-like belly buttons heal over easily because their skin is thin and soft. It is easier to see the belly button of a hairless cat and can be easier on darker cats.
- The spay scar on a female cat looks almost identical and often ends up in almost the same place as their belly buttons.
- The fur coating a cat’s skin helps cover up the belly button. Even when shaved, the scar is covered by enough hair follicles to mask its look.
- Cats, both male and female, have many nipples (between 4 and 8), and the nipples are often in a similar location to where the belly button might be located, making it harder to differentiate between.
It is a combination of factors that create the unique looking belly button on a cat that differs so greatly from a human. The two main reasons your cat’s belly button looks so different from your own is because of the thickness of the cat’s skin in comparison to humans. People have very thick skin that does not heal as easily as a cat. This leaves a larger scar.
The other reason the belly button looks so different is because of the way the umbilical cord is handled. A human is clipped or tied by a doctor, but a mother cat will simply bite her kitten’s umbilical cord off. Even when kittens are born in a vet clinic, unless the vet sees the mother cat struggling, they will not interrupt the process she has.
Most of the placental animals have belly buttons that look more like cats than humans. The difference in how the belly button forms depend on the fur of the animal, the skin’s thickness, how the abdominal wall heals, and the way the mother handles the umbilical cord after birth.
