May 31, 2023

Puppies Are Born Deaf and Blind

Welcome to our Peculiar Pet Facts series, where we investigate the oddities of our pets and explore the science behind them.

If you’re looking for an “Aww, so cute!” moment in your day, you can’t go past newborn puppies — tiny squeaking bundles of fluff. But if you take a closer look at those balls of fluffy cuteness, you’ll notice something a little peculiar — their eyes are closed. Most people are probably aware that puppy’s are born blind (their tightly shut eyelids kinda give that away), but did you know that puppies are also born deaf?

Being born blind and deaf doesn’t affect a pup’s ability to find their food (milk from their mom), though. Learn the origins behind why puppies are born blind and deaf and how their nose helps them out during those first few weeks.

Temporary Silence and Darkness

Puppies are born with their eyelids and ear canals closed to protect their delicate eyes and ears that aren’t quite done developing. A pup’s eyelids open when they are about 2–3 weeks old. But their sight isn’t fully functional just yet: their eyes still need a little time to develop, so you might look like a fuzzy blob to them. Their ear canals open around three weeks of age, allowing them to hear for the first time. They’ll probably learn the sound of the food bowl pretty quick after that!

Smell First, Sight and Hearing Later

Because newborn puppies can’t see or hear, they rely on their sense of smell to help them find their way around — although as newborns, the only thing they’re probably interested in finding is their mom and her milk. To do this, puppies use their vomeronasal organ (also called Jacobson’s organ) to detect pheromones from their mom. Pheromones are chemical signals that are released into the environment as a method of communicating with other dogs. The vomeronasal organ, which is tucked into the bottom of the nasal cavity and just above the roof of the mouth, is thought to be involved in communications related to parental (e.g., Where’s my mom?), social (e.g., Who peed on the fence?) and reproductive (e.g., Which female is in heat?) situations.

“Underdeveloped” Puppies Help the Pack Survive

Thinking about what a puppy’s cousins in the wild need to do to ensure survival can help with understanding why puppies are born deaf and blind. Dr. Stanley Coren, who writes the Canine Corner for Psychology Today, explains that the amount of development in a newborn mammal can be related to whether they are prey or predator.

For example, cows have a relatively long gestation (around nine months) and when the calf is born, its brain is fully formed. It can hear, see and run well enough to keep up with the herd, which is important in order to run away from predators.

Canine species on the other hand need to hunt to survive. Dr. Coren explains that if a female is pregnant, it’s probably going to slow her down and make it hard for her to help the pack in a coordinated hunt. The relatively short gestation period of canines (around two months) is an advantage because it allows the mother to regain mobility quickly. She can hide the puppies safely in the den while looking for food, and because hunts can be days apart, she still has plenty of time to care for her blind and deaf puppies.

What Do Puppies See When They’re Able To?

Once a pup’s eyes are fully developed, their vision is better than ours in some ways and worse than ours in other ways. Dogs have more rods (that detect light levels and motion) in their retina than us, so dogs can see better in low light and can identify moving objects better. That makes sense given their ancestors had to hunt moving objects to survive.

Colors are a different story. People have three types of cones in their retina (red, green and blue) while dogs only have two types (blue and yellow). Cones are sensitive to wavelengths of light (colors) and enable fine details to be seen. As well as having an extra type of cone, people typically have a greater number of cones than dogs. This means that the very popular myth that dogs are colorblind is false — dogs do see color, just not as many colors and the colors aren’t as vibrant.

What Do Puppies Hear When They’re Able To?

A puppy with fully developed hearing is much better at hearing than us. Dogs can hear higher pitched sounds, quieter sounds and sounds further away compared to people. They also have muscles in their ears that can tilt, rotate and lift, independent of each other, to detect where a sound is coming from. Finally, they have a longer ear canal which helps carry sounds to their eardrum. That’s why your dog can hear things you can’t.

Blind and deaf newborn puppies may seem a little peculiar, but it’s completely normal for canine (and some other) species. A pup’s super-sensitive scent-smelling skills easily help make up for their temporary lack of sight and hearing.