Why do puppies not hear at birth? “So they’re spared from hearing momma dog complaining about them” would say a joke, but turns out there are actually several plausible reasons as to why puppies don’t hear at birth and it has to do with the way this species evolved. As much as being born without the ability to hear may sound counterproductive from an adaptive perspective, there must have been some sort of evolutionary advantage for mother dogs to give birth to puppies who are unable to see or hear over being able to see and hear from the get-go. In this article we will be covering and discovering some interesting facts about a puppy’s sensory development and growth.
At some point, as animals evolved, they were divided into precocial and altricial species. The precocials had long pregnancies that led to developed offpsring; whereas the altricial had shorter pregnancies that led to underdeveloped offspring. When it comes to dogs, they’re categorized as altricial animals. This means that their pregnancies are short and puppies are born blind and deaf, with poor motor skills (they can only crawl for short distances) and the inability to regulate their body temperatures or eliminate on their own, leaving them in a pretty much helpless state. Several animals other than dogs are altricial too and that includes the vast majority of birds, cats, marsupials and humans are classified as altricial too!
Out and Off You Go!
As much as being in an helpless state can sound like a great disadvantage, Mother Nature must have sure have known what she was doing considering that dogs have made it so far in their long evolutionary history. There must have therefore been some adaptive advantages. First of all, one must consider the dog’s evolutionary past as hunters. A pregnant canine would have a hard time running around hunting for many months in row, so their gestation period is relatively short (an average of 63 days versus the 342 days of a mare). Getting the pups out of the womb quickly therefore offered a good adaptive advantage, explains Stanley Coren, Professor Emeritus in the Department of Psychology at the University of British Columbia, in an article for Psychology Today.
No Thumb Twiddling
On top of a short pregnancy, a dog’s ancestors had hunting and feeding habits that allowed them some free time. After gorging themselves with food on the day of the kill, they would often have ample of time in between hunts. This spare time was no time for thumb twiddling though. Instead, these prandial pauses worked great for allowing mothers sufficient time to cater to their helpless infants. Then, when it was time again to hunt and eat, mothers could temporarily leave their pups behind in a dry, warm den. With a dedicated mother and a safe place to stay, the pups’ sense of hearing could wait a couple of weeks without no apparent hindrance.
Grand Opening Day
With the ear canals closed shut, puppies are unable to hear and are unresponsive even to loud noises for a couple of weeks. Silence is important during this time as a puppy’s auditory system is very vulnerable and fragile. Exposure to sound waves during this time could potentially cause great damage as their auditory apparatus is not ready to handle this stimulus, explains Tom Davis in the book “Why Puppies Do That: A Collection of Curious Puppy Behaviors.” So when do puppies ears open? Generally, roughly around 10 days, the puppy’s ear canals will open slightly and at 14 days the pups begin to hear some sounds. The pup’s ears should then become fully open and operational by 3 weeks of age, explains veterinarian Race Foster.
With the helpless neonatal stage being left behind, pups are growing rapidly and getting ready to meet the world. With eyes and ears fully operational and the ability to walk around, puppies are exploring the world and responding to the many olfactory, visual and auditory stimuli that impinge on their sensory receptors. After undergoing the transitional stage of development, puppies are therefore getting ready for the primary socialization period, the most critical time for social development which starts when the pups are still in care of the breeder and continues when the pups are sent to their new homes.