Surprising Dog Facts - Senses, Behavior and World Records

A young Bernese mountain dog
A young Bernese mountain dog | Source

Wonderful Pets

Many people think that their dog is the cutest, cleverest, most affectionate or greatest dog in the world – and of course, they’re right! Dogs can develop a wonderful relationship with humans. Although their thinking capacity is not as advanced as ours, dogs have some abilities which surpass those of humans. They are also more intelligent than many people realize.

In addition to being our friends and beloved members of our family, dogs can be trained to help us and seem eager to do so. For example, dogs can help people with hearing, vision or movement problems. Some dogs can detect specific diseases and disorders, including some types of cancer, an approaching seizure in someone with epilepsy and low blood sugar in a diabetic person.

I’ve had dogs as companions since I was a child. All of them have been much loved. The photographs in this article include pictures of the present dogs in my family as well as some of my past dogs.

Sam with his head resting on my foot
Sam with his head resting on my foot | Source

A Dog's Sense of Smell

  • A dog's most important sense is their sense of smell, which is far more advanced than ours. A human’s nose contains around 5 million olfactory (smell) receptors; a dog’s nose contains from 125 million to 300 million olfactory receptors, depending on the breed.
  • In general, the dog breed with the largest number of smell receptors is the bloodhound, although individual dogs of another breed may have a better sense of smell than an individual bloodhound.
  • Smells are interpreted in the brain. The area of a dog’s brain that deals with odors is about forty times larger than the corresponding area in the human brain (in proportion to the total size of the brain).
  • We know that dogs can detect the scents given off by specific people and can be used for tracking. Specially trained dogs can also smell humans buried in avalanches and disaster zones and can detect drugs or explosives using their sense of smell.

Trained Dogs Sniff Out Cancer

Dogs That Detect Medical Problems in Humans

Some dogs can detect cancer in the human body by smelling certain chemicals in a person's breath, urine or stool. The hope is that trained dogs will be able to discover cancer in its early stages when it has the best chance of a cure. Once researchers identify the chemicals that the dogs are responding to, they may be able to create a device that detects the chemicals.

Certain dogs can tell when a person is about to have an epileptic seizure, although researchers are not sure whether the dogs are using their sense of smell or detecting some other signal to inform them of the imminent seizure. Owners report that their dog’s warning behavior gives them time to get to a safe place and prepare themselves for the seizure. The warning behavior may include the dog pawing their owner, pushing the owner so that they sit down, or standing still and staring at the owner. The owner learns to recognize their dog's particular warning.

Some dogs have also been able to detect low blood sugar in diabetics or an approaching migraine or heart attack. They are thought to be able to detect chemicals or chemical changes in a person's sweat, which indicate that the person is in trouble, but they may also be responding to changes in a person's behavior.

A beagle enjoying the water
A beagle enjoying the water | Source

A Dog's Vision

  • Dogs can see better in dim light than humans because their retina (the light-detecting layer at the back of the eyeball) contains more rod cells than our retina. The rod cells detect shades of grey and need less light to function than the cone cells, which detect color.
  • A common misconception is that dogs see only shades of grey. In fact, their retinas contain cones and they can see some colors.
  • A human retina contains three types of cones. The retina of a dog contains only two types of cones. Therefore dogs are unable to distinguish as many colors as humans can.
  • Researchers think that a dog sees shades of grey, brown, yellow and blue.
  • Dogs cannot distinguish colors in the red to green range in the visible light spectrum. These colors are thought to look like a shade of grey or yellow to a dog.
  • A red toy on green grass would be hard for a dog to see, since the toy would blend into the background.

Dylan is our Leonberger. In this picture he's a puppy.
Dylan is our Leonberger. In this picture he's a puppy. | Source

A Dog's Sense of Hearing

  • The higher the frequency of a sound the higher its pitch.
  • Humans hear sounds with frequencies of about 20 Hz (Hertz) to 20,000 Hz, although the range varies slightly in different people. Older people tend to lose the ability to hear the higher frequencies of sound.
  • Dogs hear sounds with frequencies of approximately 40 Hz to 60,000 Hz, so they can hear ultrasonic sounds - high pitched sounds that we are completely unaware of.
  • Dogs have far more muscles to move their ears than humans do, which helps them to locate the source of a sound.

Dogs Can Sense Human Emotions

Dog Intelligence

Although dogs aren't as mentally capable as humans, researchers are discovering that they are more intelligent than was previously thought.

According to Dr. Stanley Coren, a canine researcher at the University of British Columbia, dogs have the intelligence of a two-year-old human child. He says that they can understand about 165 "words" (in the form of spoken words or gestures) and that the most intelligent dogs can understand up to 250 words. Dr. Coren also says that a border collie named Rico understood 200 spoken words.

In addition, Dr. Coren says that dogs can count up to four or five. They can also do very basic arithmetic. They know that 1 + 1 = 2 but doesn't equal 1 or 3, for example.

Dog Reacts to Discovery That He Stole Cat Treats

Assistance Dogs

Assistance dogs may be guide dogs for visually impaired people, hearing dogs for hearing impaired people or service dogs to help people with mobility, medical, psychiatric or behavioral problems.

Medical response dogs may be trained to respond to their owner's low blood sugar or upcoming seizure or to bring medications or the telephone to their owner. They may even be trained to trigger a specially adapted phone to dial 911 (the emergency phone number). They can bark to attract someone's attention, help to reorient a person after a seizure and carry health information for medical personnel.

Service dogs can help people with limited mobility by opening and closing doors, turning lights on and off, fetching, transporting and depositing objects, pulling wheelchairs, opening and closing cupboards and drawers, carrying messages to caregivers in other rooms and helping a person balance as he or she walks. They can also help to remove clothing and pull a blanket up or down over their owner when the owner is in bed. They can even move paralyzed arms or legs back into their correct positions.

Sam and Scala sleeping in the car after a long and enjoyable hike
Sam and Scala sleeping in the car after a long and enjoyable hike | Source

More Dog Facts

  • The normal heart rate of a resting dog is 70 to 160 beats per minute, depending on the size and fitness of the dog. Larger breeds have lower heart rates than smaller breeds. An adult human's resting heart rate is around 60 to 100 beats a minute.
  • A dog's normal body temperature is about 101 degrees Fahrenheit (38 degrees Celsius), compared to 98.6 degrees Fahrenheit (37 degrees Celsius) in a human.
  • Dogs do sweat, but they do this mainly through the pads of their paws. Their panting helps to cool them down when they are hot.
  • Individual dogs may favor the use of either the left front paw or the right front paw to touch or move objects. These dogs exhibit "handedness", just as humans do.
  • A dog has three eyelids - an upper and lower eyelid like humans, plus a third eyelid called the nictitating membrane.
  • The nictitating membrane is opaque and moves over the eye in a horizontal direction instead of in a vertical direction.
  • At rest, the nictitating membrane is located in the inner corner of the eye, in front of a tear duct.
  • When a dog blinks, the nictitating membrane transports lubricating tears over the eye.

A Siberian husky with heterochromia (eyes of two different colors)
A Siberian husky with heterochromia (eyes of two different colors) | Source

Siberian huskies are prone to heterochromia. The condition arises due to a genetic variation. It doesn't affect the dog's vision.

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Zeus, The World's Tallest Dog

Dog World Records - Oldest and Tallest

The following statistics have been reported by Guinness World Records and are current as of early 2016. There may be even more impressive records than these, but they haven't been officially recorded.

  • Until 2011, the world’s oldest living dog was Pusuke from Japan, who was born on April 1st, 1985. Pusuke died on December 5th, 2011, at the age of 26.
  • Since Pusuke's death, there hasn't been an officially recognized oldest living dog.
  • The longest lived dog ever was Bluey, an Australian cattle dog. His lifespan was 29 years and 5 months. Bluey died in 1939.
  • Until 2011, the tallest dog was Giant George, a Great Dane, who was 43 inches tall (measured from paws to shoulder).
  • George weighed around 245 pounds and slept alone on a queen sized bed. He was born on November 17th, 2005 and died on October 17th, 2013, shortly before his eighth birthday.
  • In 2011 the Guinness tallest dog award was transferred to Zeus, also a Great Dane, who was 44 inches tall. Unfortunately, Zeus died in 2014 at the age of five. He still holds the record for the tallest dog ever.
  • There are photos of larger dogs than George and Zeus circulating on the Internet, but their sizes have not been officially recognized. In at least one case the dog's photo was found to have been digitally altered to make the dog appear larger than he or she really was.
  • Currently, there is no living dog officially designated as the world's tallest.

Misha, my Labrador retriever
Misha, my Labrador retriever

Some More Dog Records

  • The smallest living dog in height is Milly, a female chihuahua who was 3.8 inches tall on February 21st, 2013.
  • The smallest living dog in terms of length is Heaven Sent Brandy, another female chihuahua. She was six inches long from her nose to the tip of her tail on January 31st, 2005.
  • The dog with the longest ears is Harbor, a black and tan coonhound. His left ear was 12.25 inches long and his right ear was 13.5 inches long on June 8, 2010.
  • The largest recorded litter of puppies is 24. The puppies were born on November 29th, 2004. Their mother was Tia, a Neapolitan Mastiff. There were nine females and fifteen males in the litter. Unfortunately, not all the puppies survived.
  • The oldest known breed of dog is the Saluki. According to Guinness World Records, the Saluki first appeared as a distinct breed around 329 BC. Ancient art suggests that the breed or its immediate ancestor may have existed thousands of years before this, however. The dog was kept and respected by the royal family of Ancient Egypt, who mummified it after death.
  • The fastest speed at which a dog can run is difficult to determine, since it depends on the distance traveled. The fastest dog breed is generally thought to be the greyhound, which is said to be able to run at up to 45 miles an hour.

A female Saluki
A female Saluki | Source

The Saluki has long legs, a slender body and a long and narrow head, like a greyhound. It also has floppy ears. The breed has a variety of colors.

Milly, The World's Smallest Dog

All Dogs Can Be Winners

A well-trained dog is a great pet and a great friend. Reading dog statistics and achievement records is interesting, but dog owners know that their pet doesn’t need to set a world record in order to be a top dog!

Further Reading - The Mental Abilities of Dogs

In this report from the American Psychological Association, Stanley Coren describes dog intelligence.

The Psychology Today magazine describes Dr. Coren's report on the ability of dogs to solve very basic math problems.

© 2011 Linda Crampton

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Comments 31 comments

kafsoa profile image

kafsoa 5 years ago

This is a nice hub about dogs and nice video too:)

AliciaC profile image

AliciaC 5 years ago from British Columbia, Canada Author

Thank you, kafsoa. It's nice to meet you!

Fossillady profile image

Fossillady 5 years ago from Saugatuck Michigan

Wow, you have assembled a lot of dog facts! Amazing work which can provide an excellent reference. Especially when we can't remember half this stuff when we need I saw a documentary on dogs that detect cancer. They are amazing animals with sweet souls! Thanks for sharing Alicia

AliciaC profile image

AliciaC 5 years ago from British Columbia, Canada Author

Thank you very much, Fossillady. It is wonderful how dogs can help us as well as be our companions.

kashmir56 profile image

kashmir56 5 years ago from Massachusetts

Hi AliciaC, great well put together hub on dog facts !

Vote up !!!

GetSmart profile image

GetSmart 5 years ago

Great hub! I always knew one of my dogs was right pawed, my son found my belief to be quite funny though. I will be showing him this when he comes over to visit. Thank you for this information!

Simone Smith profile image

Simone Smith 5 years ago from San Francisco

Absolutely fascinating, AliciaC! I am especially intrigued by the cancer smelling ability. Dogs are amazing!

b. Malin profile image

b. Malin 5 years ago

Wonderful Hub and Pictures, and who doesn't love a Dog...I had heard about Dogs that are able to smell Cancer on certain individuals, long before the Doctors are aware.

AliciaC profile image

AliciaC 5 years ago from British Columbia, Canada Author

Kashmir56 - Thank you very much for the visit and the vote!

GetSmart - Hi! I've read that other animals, such as parrots, exhibit handedness too. It's a very interesting topic to study. Thanks for the comment.

Hi, Simone. Thanks for commenting! It certainly is interesting that some dogs can smell cancer. I hope scientists soon discover what chemicals the dogs are responding to. Hopefully this discovery will help us understand cancer better, which might then enable us to develop better treatments.

Thanks for the visit and the comment, b. Malin. Yes, it's amazing what dogs can do!

Chatkath profile image

Chatkath 5 years ago from California

Great Hub Alicia, Dogs are so amazing, I recently saw a show on their ability to detect cancer too, what an incredible animal! And they have also solved so many cases, with their ability to track and smell. What would we do without them? Thank you so much for sharing.

AliciaC profile image

AliciaC 5 years ago from British Columbia, Canada Author

Hi, Chatkath. I think dogs are amazing too! Perhaps they have other interesting abilities which we haven't discovered yet. Thanks for the comment.

marcoujor profile image

marcoujor 5 years ago from Jeffersonville PA

How intuitive to be able to detect the forewarning signs of a seizure... dogs are so utterly amazing and lifesaving.

Thank you, Alicia~~ this was great~~ Voted USEFUL & UP!

AliciaC profile image

AliciaC 5 years ago from British Columbia, Canada Author

Thank you very much for the comment and the vote, marcoujor! It's great to hear from other dog lovers. I agree with you - dogs are wonderful animals.

prasetio30 profile image

prasetio30 5 years ago from malang-indonesia

This was really useful information. I don't know about dog's behavior. Thanks for writing this. You always teaching us new and interesting things. Rated up. Have a nice weekend!


AliciaC profile image

AliciaC 5 years ago from British Columbia, Canada Author

Hi, Prasetio. Thanks for the visit and the rating. I hope that you have a nice weekend too!

Ingenira profile image

Ingenira 5 years ago

Amazing information about dog ! Wow !

Dog can detect chemicals or chemical changes in a person's sweat, and how sick he is. That's really extra-ordinary. Voted up and awesome !

AliciaC profile image

AliciaC 5 years ago from British Columbia, Canada Author

Thank you very much for the comment and the vote, Ingenira. I think dogs are extraordinary too!

Just Ask Susan profile image

Just Ask Susan 5 years ago from Ontario, Canada

Alicia I enjoyed your hub very much. I have to ask is Ryan and Scala Leonbergers?

AliciaC profile image

AliciaC 5 years ago from British Columbia, Canada Author

Thanks for the comment, Just Ask Susan. Yes, Ryan and Scala are Leonbergers. Scala and Sam are unfortunately no longer alive, but Ryan and Misha are.

tonymac04 profile image

tonymac04 5 years ago from South Africa

Wonderful and fascinating Hub. Found the cancer detection ability very interesting indeed.

Love and peace


AliciaC profile image

AliciaC 5 years ago from British Columbia, Canada Author

Hi, tonymac04. Thank you very much for your comment. Best wishes to you, too.

James A Watkins profile image

James A Watkins 5 years ago from Chicago

I so enjoyed this awesome article. I love dogs! Aren't they great? :D

AliciaC profile image

AliciaC 5 years ago from British Columbia, Canada Author

Thank you for the comment, James. Yes, dogs are great!

daisyjae profile image

daisyjae 5 years ago from Canada

I like your hub, lots of interesting info on dogs. Cute pics too.

AliciaC profile image

AliciaC 5 years ago from British Columbia, Canada Author

Thank you very much, daisyjae.

paradigmsearch profile image

paradigmsearch 5 years ago from USA

This is an extremely well researched and knowledgeable article. Many thanks! Rated up here, there, and everywhere. :-)

AliciaC profile image

AliciaC 5 years ago from British Columbia, Canada Author

Thanks you very much for the comment and the rating, paradigmsearch! I appreciate them both.

vocalcoach profile image

vocalcoach 5 years ago from Nashville Tn.

I can't begin to tell you how much I enjoyed this hub. I am a dog lover - in fact I prefer dogs to people :) Wonderful facts. Thanks for all the research. I will FB this and will also forward on to friends. Voted up and across. vc

AliciaC profile image

AliciaC 5 years ago from British Columbia, Canada Author

Thank you so much for the comment and the votes, and for sharing the hub, vocalcoach! I love dogs too, and I love to learn new information about them.

Eiddwen profile image

Eiddwen 5 years ago from Wales

What a great hub and I have to vote up up and away here.

thank you so much for sharing.

Take care and have a great day.


AliciaC profile image

AliciaC 5 years ago from British Columbia, Canada Author

Thanks a lot for the comment and vote, Eiddwen. I love dogs and I love writing about them!

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    Linda Crampton (AliciaC)1,242 Followers
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    Linda Crampton is a teacher with an honours degree in biology. She loves to study nature and write about animals and plants.

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