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Puppy Development and Of Course the Science!

Nothing is quite as adorable as a puppy, right? Maybe a kitten? That's an age old debate of dogs vs cats, we don't want to get into that here.

We do however want to discuss: P-U-P-P-I-E-S!

Puppy breath, squishy rolly-polly tummies, sleeping babies, funny little personalities and their sweet nature are hard to resist. But you know they go from the cute babies to what many consider baby sharks with razor sharp teeth, no bladder control; pottying everywhere, jumping, chewing, barking, crying, whining, lack of impulse regulation and a constant on button. Fun right? I get the draw of these magnetic creatures but the reality is having a puppy is a very time consuming, difficult, often inconvenient on a person's typical routine, added responsibility, financial investment and if we are lucky, a 15 year commitment. Puppies are, in a nutshell, A LOT!

Our goal is to help educate people on all aspects of a puppy from their relationship with their mom, littermates, all the way up to 18 months. We are committed to helping reduce the return rate of puppies being returned once they hit adolescence and adulthood. While we recognize that therE are many contributing factors to a dog's behavior, it is only beneficial to gain a broader and specific understanding of puppy behavior, long term implications of our role in our puppy's life and how to grow a calm, confident, mentally sound adult dog. With that in mind, let's discuss puppy beginnings.


To truly appreciate the magic of a puppy and how delicate and resilient they are, we first have to understand the magnificent science and development of canine gestation and newborn puppies. The approximated time a female dogs pregnancy lasts is 63-65 days, there are always variables but a general rule of thumb is that pregnancy lasts between eight to nine weeks. The little life begins as a fertilized egg, that nestles inside its mothers womb as only four cells but quickly multiplies into 64 cells, forming a head and spine and eventually a full grown puppy.

So what does a developing puppy in utero have to do with growing a healthy minded puppy and eventually a well balanced dog? More than you think! Studies show that prenatal stress increases the risk of adverse pregnancy outcomes. Prenatal stress can disrupt the maternal immunity that moms pass on to puppies in the womb as well as inhibit healthy levels of endocrine and nervous system development. We really have to embrace all the research that breaks down numerous reasons a stressed mom can literally create more fearful, anxious and nervous puppies. Those negatively felt emotions can stay with a puppy through development and into their adult years, this is turn can make typical fear impact periods and normal development that much harder for puppies that experienced high levels of stress while growing in their mom's womb.

Let us summarize the scientific research below:

  • When cortisol levels are extremely high, the enzyme that inactivates cortisol protecting it from reaching the placenta is broken down and some passes through the placenta to the developing puppies.

  • Puppies receiving larger than typical shielded levels of stress hormones receive extra cortisol as information that the world is scary.

  • Higher risk of adverse pregnancy outcomes are associated with prenatal stress

  • The maternal immune system is compromised more

  • The endocrine system is weakened.

  • The nervous system can experience improper development through the parasympatheic, sypmathetic and dorsal vegal state.

  • Parasympathetic or ventral vagal nerve is responsible for social interaction, connection and cognition.

  • Sympathetic nervous system connects the internal organs to the brain by spinal nerves and when stimulated the nerves prepare the puppy for stress by increasing the heart rate, increasing blood flow to the muscles and decreasing blood flow to the skin.

  • The sympathetic state can be chronically activated for the developing puppy to have the feeling of danger and the fight or flight response engaged.

  • The Dorsal vagus is a large primitive nerve that goes down the spine and plays a role in controlling breathing, lungs, hearts/as to moderate too rapid heartbeats, and stomach/digestion. Mom can transfer dorsal vagus disregulation to developing puppies so that her freeze state is activated when her life and her puppies' lives are so threatened she must immobilize herself for survival.

  • Higher brain functions such as learning, expressing body language and communicating at the lowest level of reactivity and escalation are dependent on how well dogs are able to process incoming information at the sensory and emotional levels. High fear levels impede healthy brain functioning and development.

  • Prenatal Stress has been linked to abnormal cognitive, behavioral and psychosocial outcomes in both humans and animals.

  • Research shows brain regions such as the hippocampus, amygdala, corpus callosum, anterior commissure, cerebral cortex, cerebellum and hypothalamus are all affected by prenatal stress levels.


Now that we have summarized the importance of a stress-free momma dog and pregnancy, for both mom and puppies, let us look a little closer at what happens developmentally after birth.

  • Birth - 2 weeks:

    • Very dependent stage of development. Puppies have tactile and taste senses only. They are completely dependent on their mother. Puppy socialization is completely dependent on mom.

  • 2-4 weeks:

    • Awareness stage of development. Puppies begin to open their eyes, start walking, hearing and smelling develop and teeth start coming in. They become aware of their environment and their siblings.

  • 4-6 weeks:

    • Individual wills and beginning socialization develop in this stage. Puppies begin learning life skills such as pottying on their own and develop independence. They also learn social skills from each other during this time.

  • 6-8 weeks:

    • Socialization and training stage of development. We start basics such as come, sit, down and look. Puppies are also learning bite inhibition and social rules. We should start potty training with all positive methods.

  • 8-12 weeks:

    • First Fear Impact Period/Critical Socialization Period. Puppies can develop negative learning histories and are highly sensitive during this time. It is best practices to keep puppies with mom and siblings until 8 weeks old for optimal social skills and avoid a predisposition to separation anxiety and other anxious behaviors. It is also crucial to keep everything as neutral to positive as possible and know how to create resilience and bounce back from any felt negative experiences. Curiosity coupled with apprehension about the world and subsequently their experiences in it. Start training to noises, novel objects, new people, other animals and environments. Vaccines have not been completed so choose play groups, spaces and social outings very carefully. Potty training continues.

  • 3-6 months:

    • The "crazy puppy" stage. Puppies begin to leave behind their fear impact period and become very bold and excitable with seemingly relentless energy. Around 4 months of age baby teeth start to fall out so this is a heavy chewing time because developmentally their adult teeth are coming in, with associated painful gums which results in a drive to chew a lot without discerning appropriate chews from non-approved chew objects. Potty training should be coming together nicely as pups are able to have more bowel control. Avoid the human easy-way-out by giving corrections for the excess energy and chewing instead, keep that basic positive reinforcement and environmental management strong during this time.

  • 6-18 months:

    • This is the "get a puppy- they said it would be fun stage." Sexual maturity hits at around 6 months of age. A second critical socialization/fear impact period develops (sometimes seen as early as 4 months). What was once a confident puppy from the previous developmental stage may now resemble more of a dog than a puppy that is more reactive, more independent, has what appears to people as less impulse control and one of the most challenging time frames in puppy development. Sadly, this could also be said to be the unfortunate time many people give up their responsibility of a lifetime commitment to their pup. Emotional maturity is a work in progress with some dominant tendencies, asserting their will, temperament develops to more consistency, and structure within the human and canine family relationships develops during this time. Always ask yourselves during this time what learned associations am I creating for my puppy?

So what is YOUR JOB for your puppy?

It goes without saying every puppy is an individual. Even though their developmental periods and similar growing pains like learning histories, bite inhibition and potty training can be a more shared experience, above all each animal just like each person, has their own genetic, physical and mental composition. With that being said I would like to outline below a more general training plan for puppies, as many people think they want a puppy, even two, and quickly realize they simply bit off more then they can chew!

  • Potty training

  • Positive crate training- see our Zen Den Blog

  • Enrichment plan

  • Socialization plan-experiences, spaces, places, dogs, other animals, variety of people, sounds, visuals,. This is imperative. You cannot oversocialize a developing dog.

  • Exposure to novelty

  • Basic communication cues

  • Training Play with toys

  • Leash work

  • Force-free exercises for grooming, handling and bathing

  • Vet trips and outings just because

  • Live training-Immersion learning

  • Puppy play dates and walking buddy systems

  • Decompression Nature walks-long leash work

  • Calming exercises

  • Threshold work

  • Mat conditioning/Place

Surprise! The training plan doesn't just stop with the puppy goals above. Your learning level and behavioral plan would generally be;

  • Science-based positive reinforcement training methods

  • No inhumane aversive training methods

  • Continuing education via Podcasts, books, blogs, videos, local behaviorists

  • Your behavioral follow through

  • Your patience level

  • Your consistency in repetition and frequency

  • You setting up structure, boundaries and environmental management

  • Being proactive instead of reactive

  • Putting in the work

  • Commitment to the process

  • Realistic expectations and goals especially in line with your puppies development

  • Expecting more from yourself then your puppy

  • Satisfying your dogs needs and drives; mental, physical and behavioral

  • Knowing when you need professional intervention

I truly hope this helps puppy parents, rescues, fosters and anyone who is responsible for raising a puppy. We want to help grow your behavioral IQ while giving you a deep understanding of how puppies develop from gestation all the way to adulthood. The more we understand, the more empathetic and knowledgeable we can be in our work with our puppies. You are the major difference between a happy, well socialized, mentally, physically and behaviorally balanced dog versus one that is blamed for struggling in our human world with our human rules. Now, let's go save more puppies and grow alongside them through our holistic behavioral work!

Meet the Behaviorist, Jennifer Caves, M.Psy, CGC:

"Welcome dog lovers and all dogs! I am the founder and Canine-Human Educator for REAL Animal Sanctuary and Behavioral Solutions. We consider our work to be rooted in science and driven by ethics. Our passion meets purpose mission is unique in that we empower and educate people with a lifelong skill set to help any dog they share their life with currently or in the future. Dogs are incredibly resilient and intelligent and when the humans in their life know the how, why and successful implementation of behavioral principles- our dogs become happy, healthy and healed.

I have my Masters in Psychology and Canine Good Citizen Certification through the AKC. I have literally been rescuing animals since I was 16 years old with 15 years of behavioral experience. I consider it a privilege to work with you and your dog!"

Contact Jennifer by visiting


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Who is Dallas Dog?

Our rehabilitation efforts address the physical and emotional needs of rescued animals and prepare them for the second chance they deserve. You can make a difference by fostering, adopting, or making a donation toward these worthy animals.

Thank you for supporting Dallas Dog. Our mission is to create a safer place for animals by rescuing and rehabilitating those who are neglected, unwanted and abused across Texas or displaced by natural disasters nearby and finding them a permanent home. You can visit our website at to follow our amazing journey.

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