Puppyhood is a whirlwind of rapid growth, big feelings, surprising behaviors, and important medical milestones. Understanding what happens at each developmental stage—from 8 weeks to 18 months—helps you stay ahead of health issues and behavior challenges. This month-by-month guide walks you through each phase with clear expectations and shows how Snuggle Puppy® Training and Snuggle Puppy® Virtual Vet powered by TeleTails can support your puppy’s entire wellness journey.
8–12 Weeks: The Foundation Stage
This is the “brand new world” phase — your puppy is adapting to everything from your home to your routine. Their brain is wide open for learning, and the habits you build now can last a lifetime.
Medical priorities in this stage include: first or second round of core vaccines, deworming and fecal testing, starting flea/tick/heartworm prevention, and a wellness exam to establish a medical baseline.
This is also a perfect time to connect with Snuggle Puppy® Virtual Vet powered by TeleTails for questions like, “Is this poop normal?", “My puppy hasn’t eaten—should I worry?”, or “How do I safely introduce my pup to my family’s dogs?” Immediate, expert advice can prevent unnecessary emergency visits and ease new-pet-parent anxiety.
Behavior & development focuses: crate introduction, name recognition, a consistent potty training schedule, short alone-time practice, and gentle handling and grooming familiarity.
How Snuggle Puppy® Training helps: In 1:1 virtual sessions, trainers can help you create a personalized potty schedule, start crate training correctly, troubleshoot nighttime crying, understand early puppy body language, and build confident handling and touch tolerance. Think of it as the instruction manual all puppies should have come with.
12–16 Weeks: The Critical Socialization Window
This period has lifelong impact. Puppies learn whether new things are “safe” or “scary,” and those impressions stick. It’s a powerful time to shape how they view the world.
Medical priorities: vaccine boosters, rabies vaccine (depending on local regulations), and continued parasite prevention. You may also notice GI issues, behavior changes, or reactions to environmental exposures.
Snuggle Puppy® Virtual Vet powered by TeleTails is there 24/7 for quick answers about mild limping, tummy upset, post-vaccine soreness, exposure to unvaccinated dogs, or dietary transitions.
Behavior & development: this is the peak social imprinting period. Teething ramps up, play becomes more adventurous, and your puppy is ready to meet the world beyond your living room. Puppies should build positive experiences with other dogs, people of all ages, vet clinics, grooming tools, and new environments.
How Snuggle Puppy® Training helps: trainers can build a customized socialization plan for your puppy’s personality, supporting safe introductions to dogs and people, confidence building, preventing early fear responses, early manners (sit, down, come), leash introduction and gentle walking, and redirection for teething and chewing. Guided socialization is one of the most powerful gifts you can give your puppy.
4–6 Months: The Adolescent Onset
Welcome to the “tween” phase. Your puppy is curious, bold, sometimes mischievous, and definitely testing the world around them.
Medical priorities: discuss spay/neuter timing with a vet, continue parasite prevention, monitor weight and growth patterns, and address any emerging health concerns.
This is when strange things suddenly pop up: “My puppy is limping after playing,” “His stool changed today,” or “She’s suddenly scared of the trash can.” Snuggle Puppy® Virtual Vet powered by TeleTails is perfect for these quick questions—no need to wait days for answers.
Behavior & development: expect more chewing, testing of limits, bursts of independence, and a bit more stubbornness. All normal… but still a challenge.
How Snuggle Puppy® Training helps: trainers can reinforce obedience skills, build reliable recall, help manage jumping, barking, or mouthing, strengthen leash skills, support impulse control, and stop adolescent regression before it spirals. This phase can make or break long-term manners, and having a trainer beside you makes it much easier.
6–12 Months: Adolescence (“The Middle School Phase”)
Energy is high. Impulse control is still developing. The world is exciting, distracting, and full of new temptations.
Medical priorities: final boosters, possible transition to adult food, and continued parasite control. Injury risk also increases as puppies play hard, jump off things, and occasionally twist or strain something.
Snuggle Puppy® Virtual Vet powered by TeleTails can help you decide if a concern is a minor sprain or something more serious, whether your dog should rest or be seen in person, and whether a cough is normal or concerning. 
Behavior & development: boundary testing, confidence surges, new fears or reactivity, and the start of social maturity are all common at this age.
How Snuggle Puppy® Training helps: our trainers can support leash reactivity or pulling, distraction-proofing commands, advanced recall, impulse control, and behavior changes related to adolescent hormones. With professional guidance, you can prevent challenging behaviors from becoming long-term patterns.
12–18 Months: The Young Adult Phase
Now you’re shaping your puppy into the adult dog they’ll be for years to come. This phase brings more maturity but still needs ongoing consistency.
Medical priorities: annual exam, dental evaluation, baseline bloodwork, and joint and mobility monitoring (especially for large breeds).
This is a great time to check in with Snuggle Puppy® Virtual Vet powered by TeleTails for nutrition evaluations, weight discussions, long-term health planning, allergy questions, and dental care routines. 
Behavior & development: you’ll likely see more consistent behavior, deeper bonding, improved impulse control, and your dog’s true adult temperament forming.
How Snuggle Puppy® Training helps: trainers can help polish skills and strengthen reliability with polite walking in busy environments, advanced recall, social refinement, household manners, transitioning to adult routines, and addressing any lingering quirks. The goal: a confident, well-mannered adult dog you love living with.
Your Complete Support System: Health + Training = Thriving Puppies
Snuggle Puppy® Virtual Vet powered by TeleTails is perfect for symptom checks, behavioral vs. medical questions, vaccine schedule advice, parasite guidance, digestive concerns, “Should we go to the ER?” moments, and nutrition and growth questions. It’s available when you need it 24/7 — not just when the clinic is open.
Snuggle Puppy® Training (1:1 virtual training) is ideal for potty and crate training, socialization planning, obedience foundations, leash skills and manners, behavior troubleshooting, confidence building, and adolescent challenges. It’s like having your own personal dog coach through every phase.
Together, these services give your puppy everything they need — medically, behaviorally, and emotionally — through every stage of development from 8 weeks to 18 months.
