Surprising Dog Facts - Senses, Behavior and World Records

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, but there are differences in the ways in which dogs and humans perceive, analyze and interact with the world. Although their thinking capacity is not as advanced as ours, dogs have some abilities which surpass those of humans.

I’ve had dogs as companions since I was a child. All of them have been much loved. The photographs in this hub show some of the dogs that have been in my family in the past and in the present.

• A dog's most important sense is the 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, but 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 smells is about forty times larger than the corresponding area in the human 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.
• 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 these dogs will be able to discover cancer in its early stages, when it has the best chance of a cure. Another possibility is that once researchers discover what chemicals the dogs are responding to a machine can be created that will detect the same 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.

• 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.
• Many people think that dogs see only shades of grey, but in fact their retinas do 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 on the visible light spectrum. These colors are thought to all appear as a grey or yellow shade to a dog.
• A red toy on green grass would be very hard for a dog to see, since the toy would blend into the background.

• The higher the frequency of a sound the higher its pitch.
• Humans hear sounds with frequencies of about 20 Hz (Hertz) to 20000 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 60000 Hz, so they can hear ultrasonic sounds - high pitched sounds that we are completely unaware of.
• Dogs have far move muscles to move their ears than humans do, which helps them locate the source of a sound.

• 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. 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, and can even move paralyzed arms or legs back into their correct positions.

• A resting dog's normal heartbeat rate is 70 to 160 beats per minute, depending on the size and fitness of the dog. Larger breeds have lower heartbeat rates than smaller breeds. An adult human's resting heartbeat 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 only through the pads of their paws. Their panting helps 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.

According to Guinness World Records:

• On December 9^th, 2010 the world’s oldest living dog was Pusuke from Japan, who was born on April 1st, 1985.
• The longest lived dog ever was Bluey, an Australian cattle dog, who lived for 29 years and 5 months.
• The world's tallest living dog (and tallest dog ever recorded) is Giant George, a Great Dane, who was 43 inches tall (measured from paws to shoulder) on February 15th, 2010. George weighs around 245 pounds and sleeps alone on a queen sized bed. He was born on November 17th, 2005. Giant George has his own website, Twitter account and Facebook page.
• There are photos of larger dogs 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.
• The smallest living dog in length is Heaven Sent Brandy, a female chihuahua, who measured six inches (15.2 cm) from nose to tail tip on January 31st, 2005.
• The smallest living dog in height is Boo Boo, a female chihuahua who was four inches tall (10.16 cm) on May 12th, 2007.
• The largest litter of puppies is 24. The puppies were born on November 29^th, 2004. Their mother is Tia, a Neapolitan Mastiff.

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 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!