12 Fascinating Facts You Didn’t Know About Newborn Puppies

By Aly Semigran 

Newborn puppies: they’re small, they’re cute, and they’re downright fascinating.

The first few days of a puppy’s life may not be action-packed (it’s a whole lot of sleeping, eating, and pooping, as is the case with most newborns). But there are some things new pet parents should know to ensure their pups grow into healthy and happy dogs. Here’s what our vet experts had to say. 

Puppies develop and grow inside their mother’s womb for approximately two months. This is the normal gestation period (or length of pregnancy) for dogs. In the sense of development, “a newborn puppy is not unlike a premature child,” explains Dr. Margret Casal, associate professor of medical genetics at the University of Pennsylvania’s School of Veterinary Medicine.

Healthy size and weight are entirely dependent on the breed, explains Dr. Richard Wheeler, owner and practitioner at Poudre River Veterinary Clinic in Fort Collins, Colorado, and a faculty member at Colorado State University’s College of Veterinary Medicine. But ideally, all newborn puppies should double their birth weight after the first week, he says. 

Puppies can’t see or hear for the first two weeks of their lives, but they can make puppy noises. “They’ll vocalize right from the beginning,” Wheeler says. “When they are born, the mom will lick the placenta off to stimulate them.”

At around 10 days, they’ll start to open their eyes, even though they aren’t fully formed yet. “The rudimentary eyeball hasn’t formed completely until up to 10 weeks,” Wheeler describes. All puppies are born with a blue-gray color to their eyes, Casal adds. Their “true” eye color will be evident at around 10 weeks.

As for hearing, Casal says, “Most newborn puppies can hear a little bit when they are born. However, their ears are still closed until about 14 days of age.”

Dr. Bonnie Brown and Dr. Ashley Davis of New York City’s Gotham Veterinary Center point out that newborn puppies eat every two hours. Even without vision, puppies use their reflexes and instincts to find their mother’s nipple to nurse, notes Casal.

In between feedings, they sleep about 90 percent of the day, or 22 hours, Davis and Brown share.

Newborn puppies rely on their mothers to stimulate them to go to the bathroom. Wheeler says that if the mom isn’t in the picture, humans can help with this process by gently rubbing a puppy’s rear end with a wet paper towel until they urinate and defecate. 

Temperature is an important factor for newborn pups. As Wheeler points out, puppies can’t regulate their own body temperature very well. Ideally, they should be kept in a setting of 75 degrees at 80 percent humidity so their digestive tract, immune system, and other bodily processes can function normally. 

Puppies “have sharp little nails when they are born,” Casal notes. It’s typically best to wait until 4 to 6 weeks of age to clip their nails, but this can be done sooner if they are hurting the mother, she says.

They are also born with hair and fur, but the amount depends on the breed. “When they’re born, they have a puppy coat,” Wheeler explains. “As they grow over their first year, dogs that shed will shed out their puppy coats and grow their adult coat.”

Their teeth start coming in at around 4 weeks old, Davis and Brown share. Between 3 and 4 months old, they begin to lose their baby teeth to make way for their adult teeth.

As newborns, puppies will scoot and crawl around. Between 3 and 12 weeks of age, they will really start walking and improving other motor skills (including wagging their tails), Davis and Brown say. 

Puppies are most vulnerable to illnesses like parvo and distemper around 4 to 12 weeks of age, Wheeler says. Newborn puppies are also susceptible to canine herpesvirus in their first three weeks of life, which they can contract from other dogs in the household or from their mother before or after birth. Unfortunately, very young puppies who are exposed to large doses of canine herpesvirus almost always die.

A newborn puppy should not be separated from his mother and littermates before 8 weeks old and can stay for up to 12 weeks. Separating a puppy too soon can affect his health and growing immune system. “By keeping puppies with their mother, they are less likely to be exposed to infectious diseases,” Casal explains. “If you take them away, their immune system is not fully developed yet, and you’re exposing them to other things that could get them sick.”

It’s not just health that’s essential when it comes to a growing pup. Between 3 and 14 weeks of age is a critical socialization period for puppies, according to Davis and Brown.

“Puppies need to recognize and interact with dogs and other species, such as humans and cats. It is recommended to begin socialization at 3 weeks of age, as this is a period of rapid brain development. At this time, puppies are fully aware of and are able to respond to their environment.” At around 4 weeks old, puppies will start to play in groups, they add.

Once puppies are adopted and living in their new home, pet parents should take them for their first vet visit at approximately 8 weeks of age, Davis and Brown advise. “Intestinal parasites can be prevented by deworming medication and by keeping your dog in a clean environment. All puppies should have their stool checked for parasites by a veterinarian.”

Puppies should also receive their first vaccinations around this time, as the antibodies from their mother’s milk start to wear off, Wheeler adds.