All animals that are viviparous (give birth to live young instead of laying eggs) have umbilical cords.

Since mammals are gestated inside their mothers, all baby mammals are born with umbilical cords. When a baby emerges, the mother uses her teeth to chew off the cord, leaving a flat scar. This scar is what we know as a belly button. These are often harder to see than on humans and obscured by hair. You might not think your pet has a belly button, but if you look hard enough, you’ll find it. Gorillas and chimpanzees have belly buttons similar to humans in shape, however, they don’t go in or out.

There are always exceptions. Marsupials and platypuses do not have belly buttons. Baby marsupials’ umbilical cords usually fall off while in their mother’s pouch, so a scar never forms. Platypuses lay eggs, so there is no umbilical cord or belly button.

Some species of shark are viviparous and have an umbilical cord attached to their placenta.

shark belly button

A shark belly button. H/T sharks4kids.com

I don’t know of any fish that have umbilical cords. If they do exist, they would have to be viviparous and not egg-laying.

INTERESTING FACTS
  1. Baby parrots are all given different “names” at birth. After giving birth, a parrot will develop a particular call for its offspring.
  2. A giant panda baby is about the size of a stick of butter when it’s born.
  3. It takes baby rhinos five months for their horn to begin emerging.
  4. Adult meerkats essentially form collective clubs in which the duties of raising and teaching young pups are shared amongst the adults in the community.
INTERESTING VIDEO

INTERESTING REFERENCES
  1. MentalFloss.com – Do Other Animals Have Belly Buttons?
  2. Scienceline.UCSB.edu – Do cats have belly buttons? If not, then how do their offspring get their nutrients?
  3. Factinate.com – 40 Irresistible Facts About Baby Animals 

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