Puppies grow fast. That little ball of fur that fit in your hand will become an adult dog in less than a year, or in two years in the case of giant breeds. And each phase of this growth has its particularities.
Understanding what happens at each stage helps you offer what the puppy needs at the right time. It's no use wanting to teach complex tricks to a 2-month-old dog, just as it doesn't make sense to expect a 4-month-old puppy to hold it all night without peeing.
The first weeks (up to 8 weeks)
Normally you won't have the puppy at this stage, since the ideal is for it to stay with the mother until at least 8 weeks. But if you rescued a litter or are caring for a very young puppy for some reason, you need to know some things.
Puppies are born blind and deaf. Eyes open around 10-14 days and hearing starts working a bit later. In the first weeks, they basically sleep and nurse. The mother takes care of everything, including stimulating them to poop and pee by licking.
If you're raising an orphan puppy, you'll need special milk for dogs (never cow's milk), bottle or syringe, and will have to simulate the mother's stimulation with warm moist cotton on the genital area after each feeding. It's laborious and delicate. If this is your case, seek urgent veterinary guidance.
Eyes open, start walking unsteadily, first baby teeth appear. Still totally depend on mother's milk. Body temperature still not well regulated, so they need a heated environment.
Start eating mush, play with siblings, learn to control bite strength. This phase with mother and siblings is fundamental for social development. Puppies separated too early usually have behavior problems later.
8 to 12 weeks: arrival at home
This is the most common age for adoption. The puppy is already weaned, has learned the basics of living with other dogs, and is entering the most important phase of socialization.
For feeding, it needs puppy-specific food. The difference isn't just marketing: puppy food has more protein, more calories and nutrients in proportions adequate for growth. Divide the daily amount into 4 meals. Yes, four. Puppy stomach is small and it needs constant energy.
It's at this stage that you'll start the vaccine protocol. The first dose has usually already been given by the breeder or shelter, but confirm. Until completing the vaccination schedule (usually around 4 months), avoid exposing the puppy to places with circulation of unknown dogs.
One thing many people don't know: this doesn't mean you should isolate the puppy completely. Socialization is as important as vaccines. You can carry it in your arms to know different places, receive visitors at home, introduce to sounds and new situations. Just avoid putting it on the ground in parks and pet shops.
3 to 6 months: canine adolescence
Here things get interesting. The puppy is full of energy, curiosity and desire to test limits. It's the phase that most requires patience from the owner.
Baby teeth start falling around 3-4 months and permanent ones grow until 7 months. This itches, bothers, and the puppy will want to bite everything. Offer appropriate toys, freeze carrots or rubber toys to relieve discomfort. And remove from its reach everything you don't want destroyed.
Feeding can go to 3 daily meals. Some puppies start regulating appetite better and don't devour food instantly like before. Others continue eating as if it were the last meal of their life. Observe yours.
It's a good phase to start basic training. Simple commands like "sit", "stay" and "come" can be taught with short 5-10 minute sessions. Use positive reinforcement: treats, praise, play. No physical punishment.
6 to 12 months: almost adult
Small and medium breeds are getting close to adult size. Large breeds still have quite a bit of growth ahead. Either way, the puppy isn't so much a puppy anymore.
Feeding can go to 2 daily meals. Many owners keep this schedule for the rest of the dog's life, others prefer just one meal. Two usually works better to avoid excessive hunger and regulate the intestine.
If you haven't started walking regularly yet, now is the time. Puppies this age have energy to spare and need to expend it. A dog that doesn't expend energy becomes a dog that destroys things, barks too much, gets anxious. Two 30-minute walks work wonders.
Problem behaviors you let pass before become harder to correct now, but it's still not too late. If your dog jumps on people, pulls the leash too much, or has other unwanted habits, consider seeking a trainer. The sooner you resolve it, the better.
Transition to adult food
When to switch to adult food? Depends on size:
Small breeds (up to 10kg adult): around 10-12 months.
Medium breeds (10-25kg): between 12 and 14 months.
Large breeds (25-40kg): around 15-18 months.
Giant breeds (more than 40kg): may need puppy food until 18-24 months.
The transition should be gradual. Mix the new food with the old over a week, increasing the proportion little by little. Sudden changes cause diarrhea.
Things that seem like problems but are normal
Puppies sleep a lot. Like, a lot. 18-20 hours a day in the first weeks, decreasing to 12-14 hours as they grow. If your puppy sleeps all day and only wakes up to eat, play and destroy things, everything is fine.
Hiccups are common, especially after eating too fast or playing a lot. Usually pass on their own in minutes.
Eating poop (coprophagia) happens more than we'd like. Can be hunger, boredom, behavior learned from the mother, or just curiosity. In most cases, it passes with time. Keeping the environment clean helps.
Fear of random things is normal. Puppies go through "fear periods" where they suddenly get scared of things they previously ignored. Don't force, don't make a drama. Let it approach at its own pace.
Warning signs
Not everything is normal. Seek a veterinarian if you notice:
Puppy that hasn't eaten for more than 24 hours, or that is vomiting repeatedly. Dehydration in puppies is dangerous and happens quickly.
Persistent diarrhea, especially if it has blood. May be worms, virus, or something it ate that it shouldn't.
Very swollen and hard belly, different from full belly after eating. May indicate worms or something more serious.
Very quiet puppy, without energy to play when awake. Healthy puppy is active. Apathy is a sign of problems.
Intense itching, hair loss in specific areas, skin wounds. May be allergy, fungus, or mange.
In summary
Raising a puppy is work, but it's rewarding. The first months pass quickly and define much of the behavior the dog will have for the rest of its life. Invest time in socialization, be consistent with rules, and don't skip vaccines.
Each phase has its challenges. The phase of biting everything passes. The phase of not controlling pee passes. The rebellious adolescence passes. And when you look at your well-adjusted adult dog, you'll see that every difficult moment was worth it.