Yes, whales do have belly buttons.
In fact whales, dolphins and porpoises are all born with belly buttons.
The belly button is what is left after the baby whale losses its umbilical cord (aka birth cord) which is attached to the abdomen of the new-born baby whale.
During a whales gestation period (the period between conception and birth) the umbilical cord is connected to the placenta and the baby whales stomach.
Note: Depending on the species of whale the average gestation period can last anywhere from 10 – 17 months.
The umbilical cord plays a very important role in the health of the unborn baby whale as it transfers oxygenated, nutrient rich blood to the fetus, while also transferring nutrient depleted blood back to the placenta and removing toxic waste.
This filtration system is similar to that of humans (and most land mammals) and plays a major role in a fetuses development process by ensuring the child is getting the nutrition it needs to grow into a healthy newborn baby.
To prevent the baby whale from drowning when giving birth most calf’s are born tail first.
This ensures that the baby whales head isn’t submerged underwater for an extended amount of time and to make it easier for the baby to swim to the surface after birth.
After birth occurs the umbilical cord is separated from the baby whale and mother allowing the baby whale to receive food externally.
In the beginning feeding a newborn baby whale generally involves the mother producing a thick paste like milk from her mammary glands which the baby whale suckles from her nipple.
The thick milk consists largely of fat which is packed full of nutrients and is able to pass through the water without instantly breaking apart.
A baby whale may also create a seal around the mothers nipple with its tongue to help prevent milk from unnecessarily passing through the water.
When it comes to the amount of food a baby whale can eat some baby whales have been recorded consuming up to 10% of their body weight in food on a daily basis and a baby blue whale can consume as much as 150 gallons of milk per day!
Depending on the species of whale a baby whale may continue to feed on its mothers supply of milk anywhere from 6 months to 2 years or until the child is able to fully survive and hunt on its own without the need of its mothers nutrient rich milk.
Some children will continue to suckle way after the mother no longer produces milk and will not stop until they are able to psychologically separate from the mother and their dependency on her.
Eventually, the baby whale will grow into an adult and repeat the process with their mating partner.
Depending on the species most whales will reach sexual maturity between the ages of 5 – 15, however a few may reach sexual maturity at a later age.
As you can see the belly button of a whale or human is a reminder of the baby’s time within the mother’s womb and the role it played in providing the child with the nutrients it needed to survive.