Puppies can smell from the moment they are born. In fact, smell is the very first sense they rely on. Newborn puppies are born with their eyes sealed shut and their ear canals closed, so scent is their primary tool for navigating the world during their earliest days of life.
Smell Works From the First Breath
A puppy’s sense of smell isn’t just barely functional at birth. It’s already sophisticated enough to guide the puppy toward its mother’s nipples for that critical first feeding. Without sight or hearing, a newborn puppy depends almost entirely on scent and warmth to orient itself, find milk, and stay close to its littermates.
Research in related species (kittens, which share a similar developmental pattern) shows that newborns initially use both thermal and olfactory cues to find their way around. But by the end of the first week, smell takes over as the dominant navigation tool, even when warmth cues point in a different direction. Puppies follow the same general principle: warmth matters early on, but scent quickly becomes the sense they trust most.
Puppies Learn Scents Before Birth
Perhaps the most surprising finding is that puppies begin learning smells while still in the womb. A study published in the journal Applied Animal Behaviour Science tested this by feeding pregnant dogs a diet containing aniseed. Puppies born to those mothers showed a clear preference for the smell of aniseed over a neutral option. Puppies from mothers who hadn’t eaten aniseed showed no such preference.
The researchers tested some of these puppies just 15 minutes after birth, ruling out the possibility that they picked up the preference from their environment after being born. The scent preference was already locked in from prenatal exposure. This kind of prenatal olfactory learning likely plays a role in helping newborns recognize their mother. During birth, the mother licks her pups and then herself, which can transfer amniotic fluid to her nipples. Familiar scents from the womb end up right where the puppy needs to find them.
How Smell Develops in the First Weeks
While smell is present at birth, a puppy’s olfactory system continues to mature over the first several weeks of life. Here’s how it fits alongside the other senses:
- Birth: Smell is functional. Touch is also present. Eyes and ears are closed.
- 10 to 14 days: Eyes begin to open, though vision is blurry at first.
- Around 3 weeks: Ear canals open and puppies start responding to sounds.
- 3 to 5 weeks: All senses are now working together, and puppies begin exploring their surroundings more actively. Smell becomes increasingly refined as the brain’s scent-processing areas grow and form new connections.
Because smell comes online so far ahead of the other senses, it shapes a puppy’s earliest experiences and social bonds in ways that vision and hearing simply can’t. By the time a puppy can see and hear clearly, it already has weeks of scent-based memories linking it to its mother, siblings, and home environment.
The Role of Maternal Pheromones
Nursing mothers release a specific chemical signal called dog-appeasing pheromone from the skin between the mammary glands. Production begins within the first three to four days after giving birth and continues until about two to five days after weaning. This pheromone helps calm puppies and reinforces the bond between mother and litter. Newborn puppies detect and respond to it from their very first days, which is another sign of how functional their sense of smell is right out of the gate.
Synthetic versions of this pheromone are sold commercially (often as diffusers or collars) and are sometimes used to help older dogs with anxiety. The science behind those products traces back to this early-life scent bond between a mother and her pups.
The Vomeronasal Organ
Dogs have a second scent-detection system beyond the nose itself. A small structure called the vomeronasal organ, located along the floor of the nasal cavity, specializes in picking up chemical signals from other animals. It’s involved in detecting pheromones and may also play a role in taste. While researchers still don’t fully understand exactly when this organ reaches peak function in puppies, it is structurally present at birth and contributes to the pheromone detection that drives early bonding and nursing behavior.
What This Means for Puppy Owners
Because puppies rely on smell from day one, the scent environment matters more than most people realize during the first weeks of life. Keeping bedding consistent, avoiding strong cleaning chemicals near the whelping area, and allowing puppies to stay close to their mother all support normal development. Abrupt changes in the scent landscape can be disorienting for very young puppies who literally cannot see or hear what’s happening around them.
As puppies grow older and begin the socialization period (roughly 3 to 12 weeks), their sense of smell is already well established and working alongside their newly developing vision and hearing. Exposing puppies to a variety of safe, gentle scents during this window can be part of healthy early enrichment, building on an olfactory system that has been learning since before the puppy was even born.