Here are some fun facts about dogs how your new puppy is developing and growing and how dogs sense the world!

Puppy development before we even get them:

 

Gestation is about 62 – 65 days

• Eyes open between 10 and 16 days with vision more obvious between 3- 4 weeks.
• Ears open 12 -14 days and the canal continues to widen for approximately 5 weeks -although they seem to recognize sound from day one -they are more coordinated around 4 weeks.
• Nose works from day one and gets more refined as they grow and develop.
• Touch is incredibly sensitive as well as they root around for mom and food!

We pick up our puppies around 8 weeks old:

• They will have 23 baby teeth that will come in (that are razor sharp!) and will lose them all around 4 or 5 months of age (although some breeds take longer and some smaller breeds have a tough time losing their baby teeth and end up with both sets that your vet will need to have a good look at).
• They end up with 42 adult teeth (20 in the upper jaw and 22 in the lower jaw) with the molars being the last to come in around 8 months or so.

Adult senses:

Eyes

• Dogs are most active at dawn and dusk
• Their eyes are positioned differently on their faces giving most breeds a greater field of vision (humans have stereoscopic vision and a 180-degree field of view whereas some breeds have up to a 240-degree field of view and they may have a smaller field of binocular vision).
• They have a third eyelid called a nictitating membrane (that you may see when the dog is sleeping-keeping the cornea moist) that helps to protect the eyes from grasses and debris as the dog moves along the ground.
• The dog’s cornea, lenses and pupils are comparatively larger than the human eye which allows for more light to enter the eye enabling the dog to see prey better in low light conditions.
• Although they may be able to receive more light through their eyes and see objects in dim light, their visual acuity is not as keen as humans (the articles I have read suggest that dogs have approximately 20/75 vision).
• Do dogs see color? Sort of…in the eye, light receptors in the eye called rods sense light and movement and cones require a lot of light to detect color. Rods are more prevalent in nocturnal animals and cones are more prevalent in diurnal animals like us. Dogs do not have a cone concentrated area in the eye (like humans do) called a fovea which help to detect specific colors. Dogs do, however, have another structure called a tapetum lucidum (which you may see as a green reflective sheen in their eyes at night) which helps to pass light back over the retina for extra light exposure. The tapetum lucidum does not develop completely until weeks after the puppy is born. While humans have the cones that detect red, blue and green, dog’s only have the cones to detect violet and yellow-green. What you end up with is a dog that sees color the way a human does that is red-green color blind. What we would see as blue-green, dogs would see as white or gray and what we would see as green, yellow, orange or red all appear as shades of green or yellow to dogs.

Ears

• Dogs are born deaf and their ears do not open until about the 12th day and learning to differentiate the direction a sound is coming from can take months or even a year or two to fine tune.
• Dogs have a greater range of hearing than humans – Humans range is about 20 – 20,000 Hz whereas dogs hearing ranges from about 40-60,000 Hz. Some breeds have better hearing than others. There are 17 to 18 muscles in a dog’s ears (compared to our 6 to 9) that allow them to rotate the outer part of the ear (the pinnae) to pin point where sounds are coming from. Have you ever watched your dog when you’ve called it to come and seen just one ear rotate towards you while the other ear is still focused on whatever is enticing the dog in front of it?

Nose

• Amazing! Almost everyone is fascinated by how well dogs can smell. How do they do it? The bottom line is that they have a greater surface area of nasal epithelium for detecting smell which means more scent receptor cells working on every scent. Humans have about 5 million scent receptor cells working for us but a dog can have anywhere between 125 million to 300 million depending on the breed. Their noses have more curves and movement abilities – each nostril can move independently from the other – and they can channel scent further into their nose than we can. When they inhale part of the inhalation goes directly towards scent detection while the other part channels in for respiration. They possess deep in the nasal passage tiny bony structures called turbinates which work with olfactory receptors to sift out specific scent molecules. When dogs exhale the air is passed through the side slits of their nose ensuring that they do not lose the current scent that they are inhaling in the main part of their nostrils. This ability to stay on scent certainly helps with hunting or finding a mate. Moisture plays a key role in trapping scent particles for the dog to differentiate what type of scent they are detecting. You may have actually heard your dog snorting when they come upon a strong odor and a scent they are driven to follow. Moisture from their noses and mouths help to dissolve scents carried along the nasal epithelium. More of the dog’s brain is also dedicated to olfaction than ours with a specialized section set aside specifically to detect pheromones through their vomeronasal organ located in the nose. Specialized scent breeds like the bloodhound, use their ears to also help stir up scent trails along their way. They swing their heads and ears side to side low to the ground and drool or snort moisture into their noses as they pace themselves, enabling them to lift up odors and process those smells in a very efficient manner.