How does the mother dog know to bite umbilical cord off?

Mother dogs instinctively bite the umbilical cord of their puppies soon after birth to separate them from the placenta. This behavior is driven by a combination of maternal instincts and biological factors:

1. Hormonal Changes: After giving birth, the mother dog experiences a sudden drop in progesterone levels. This hormonal shift triggers a series of maternal behaviors, including biting the umbilical cord. Progesterone has been shown to inhibit maternal behavior, and research has shown that decreasing progesterone levels are closely associated with the display of maternal behaviors in various mammals, including dogs.

2. Stimulation from the Puppy: The newborn puppy's movements, crying, and licking of the mother's abdomen provide tactile stimulation that further prompts her to bite the umbilical cord. This stimulation, combined with the absence of the placenta's inhibitory cues, encourages the mother to perform the necessary tasks for pup care, such as severing the umbilical cord and ingesting the placenta.

3. Scent Marking: Biting the umbilical cord also releases scent markers, which help the mother dog recognize and identify her puppies. This scent marking behavior contributes to the formation of the mother-puppy bond and helps the mother differentiate her puppies from others in the litter.

4. Hygiene: Biting the umbilical cord helps to maintain hygiene by removing the placenta and preventing the umbilical stump from becoming infected. The mother dog may also lick and clean the puppy to remove any remaining birth fluids and promote cleanliness.

It's important to note that not all mother dogs bite the umbilical cord. Some may instinctively chew it off cleanly, while others may tear it or leave a small stump. However, the vast majority of mother dogs possess this innate behavior, which plays a vital role in the survival and well-being of their puppies.