A puppy’s journey: from a single cell to a 12-week-old puppy

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See the incredible development of a puppy inside its mother’s womb, and the remarkable changes it undergoes in its first few weeks of life.

Puppy development stages: from fertilisation to a 12-week-old puppy

The gestation period for dogs is approximately nine weeks, but in that time the most incredible transformation occurs. And once the puppy is born, it goes through even more growth and development before joining you in its new home.

Dog pregnancy week by week: From fertilisation to foetus

Weeks 1-3 

Once the egg is fertilised, this future puppy nestles inside its mother’s womb and starts a nine-week journey from only four cells to fully grown puppy. This four-celled being quickly multiplies to 64 cells, ready to form a head and spine.

Week 4 

The foetus continues to multiply and develop, and at week 4 it grows a head, eyes and its first vertebrae. At this point, the dog foetus has nearly tripled in size and has already grown to 15 mm, or as big as a hazelnut.

The foetus also develops its organs and can be seen in an ultrasound at the vet’s surgery.

Weeks 5-6 

During weeks 5 and 6, the foetus starts to look more like a puppy, with toes, nails and whiskers. The foetus’s organs have completely developed, along with its skin colour. At the six-week mark, the foetus has sex organs and begins to develop into either a male or a female.

Weeks 7-8

Starting at week 7, the soon-to-be-pup’s skeleton has developed completely, and may be seen clearly by ultrasound. In preparation for the birth, the mother will start to develop a bald spot on her stomach so that her pup can easily find where to feed from her nipples.

Week 9

From day 57, the beginning of Week 9, the puppy can safely be born, although it will usually wait until 60 to 63 days. Not all puppies are born with the coat collar of adulthood. For example, Australian Cattle Dogs (red heeler, blue heelers) are all born white.

Puppy development: From birth to 12-weeks

Puppies are born blind, deaf and toothless, and are unable to regulate their own body temperature for the first week or two. A newborn pup depends on its mother and littermates for warmth.

Week 1

A newborn puppy spends 90 per cent of its time sleeping. All its energy is used for feeding and growing, and its weight will double in the first 10 days. A newborn is unable to support its own weight yet, but can crawl and wiggle about using its front legs.

Weeks 2-3

In the second week of life, the puppy’s ears and eyes open, giving it a whole new sense of the world. At this point, the pup becomes chattier and starts to test out its vocal skills with yelps, whines, and barks. By week three, a newborn will take its first wobbly steps.

This is a time of rapid physical and sensory development for any puppy. They begin to play with their littermates, and their personalities start to become evident. They will develop bladder control and so move away from where they sleep when they need to go.

Weeks 4-11

Puppies begin transitioning to solid food at around week 4 and develop their baby teeth at week 6. In weeks six to eight a pup will learn to accept others as a part of the family. By the time the puppy reaches 10 weeks old, they might be a little scared of meeting new people.

Staying with their mother and littermates at this stage helps a puppy learn useful skills like bite inhibition, how to understand and react to normal canine communication, and their place in doggy society.

Week 12

At week 12 the puppy is ready to leave the litter for its new forever home. If you are bringing home a new puppy, one of the most fun and most challenging parts of the journey can be finding the perfect name for your pup. At this point, your new puppy’s personality will be on full display, and a guide to naming a new dog can help you with the big decision.

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