Many of us dog owners think  we know plenty about man's best friend...question is how much do you really know.  Take a look at these interesting dog facts and let us know how many you knew in the comments section below! 

#1 – Hot Dog! 

Unlike humans who have sweat glands throughout their skin, dogs only sweat through the pads of their feet. 

#2 – Where's his eyeball?

Ever seen your dog sleeping with what looks like his eyelids open?  But where is his eyeball?  Dogs actually have 3 eyelids, an upper lid, a lower lid, and a third lid called a nictitating membrane or “haw” which helps keep the eye moist and protected. 

#3 – Tail Chasers

Dogs can chase their tail for a miriad of reasons: exercise, anxiety, predatory instinct, or....they might have fleas.  

#4 – Tasting That Smell

Dogs' noses secrete a thin layer of mucous which helps them absorb scent. They end up licking their nose to sample the scent through their mouth. 

#5 – Non-Exquisite Palate 

Unlike humans who have around 9,000 taste buds, dogs only have around 1,700 (cats only have around 473!)...which is probably why they don't have a problem picking through the trash! 

#6 – Masters of the Olfactory

Contrary to their taste buds, a dog's sense of smell is 10,000 - 100,000 times more acute as that of humans.  Gentlemen, this means if it smells to you...it wreaks to them! 

#7 – Colorblind? 

Not so much...it's a popular myth that dogs only see in black and white. Dogs, in fact, see primarily in blue, greenish-yellow, yellow, and shades of gray.

#8 – You hear that?

Ever see your dog's ears perk up and wonder what they're hearing?  Dog's can hear a much higher frequency of sound than humans.  While we max out around 2,000 Hz., dogs can hear up to 8,000 Hz.  

#9 – Ohh that's what they're doing!

Dogs who kick after going to the bathroom are actually using the scent glands on their paws to further mark their territory. 

#10 – Night Vision

Through a special membrane called the tapetum lucidum, dogs can see in the dark. 

#11 – Napmasters

Dogs and humans experience the same type of slow wave sleep and rapid eye moment, which is when they dream.  Dogs, unlike humans (as you've notice) have the ability to reach the deeper dream state of sleep MUCH quicker than humans.  If/when you see the twitching and paw movements, that's when you know your dog is in a deep dream state. 

#12 – The Pearly Whites

Puppies start out with 28 teeth and eventually graduate into a full mouth of 42 adult doggie teeth. 

#13 – Lucky Pups!

Three dogs from the Titanic survived the sinking of the ship.  

#14 – Paul McCartney 

It's rumored that at the end of the Beatles song, “A Day in the Life,” Paul McCartney recorded an ultrasonic whistle, audible only to dogs, just for his Sheland sheepdog. 

#15 – Don't Skip a Beat

A human's heart beats between 60-100 times per minute.  A dog's however can vary from 60-140 beat per minute.  Large dogs range between 60-100 beats, whereas small dogs range from 100-140 beats per minute. 

#16 – Hot Blooded

Whereas humans come in at around 98.6 degrees Fahrenheit, a dog's normal temperature ranges between 101 and 102.5 degrees Fahrenheit. 

#16 – Man's Best Friend

79.9 million homes in America have a pet, or about 62% of U.S. households! 

#17 – Little Spoons

It's reported that about 45% of dogs sleep in their owner’s bed. Does your dog leave you any room? 

#17 – Doggy Burritos! 

Dogs curl up when they sleep due to an old instinct that protects their abdomen and vital organs (same reason humans cross their chest in uncomfortable positions) and keeps them warm. 

#18 – Catch Your Breath

In addition to sweating through their paws, dogs also pant to keep themselves cool.  A panting dog can easily take 300-400 breaths compared to the regular 30-40 when resting. 

Source: Vetstreet, Healthy Pet, Whole Dog Journal, About.com, Psychology Today, PBS, American Pet Products Association, Web MD, Mayo Clinic, Petfinder.com