A WARM OR DRY NOSE MEANS A DOG IS SICK
This one is probably the biggest dog health myth around. Somewhere along the line, people came to the conclusion that a cold, wet nose is a sign of a healthy dog and a warm or dry nose is a sign of illness.
Like many myths, the origins of this are not definitively known but are likely rooted in fact. Canine distemper is a deadly virus that was once quite prevalent. One symptom of advanced distemper is hyperkeratosis (thickening) of the nose and footpads. Basically, the nose and pads of the feet become hard and dry. Back when distemper was more widespread, a cool, wet nose was considered a good sign that the dog did not have distemper. While canine distemper still occurs, it is far less common today due to vaccinations.
The temperature and moisture of your dog’s nose are not miracle measurements of his health. For instance, a dog’s nose is often dry and/or warm if he has just woken up, and this is perfectly normal. However, a nose that is persistently dry and crusted might be a sign of a health problem. If you notice an abnormal appearance to your dog’s nose or any other signs of illness, contact your vet right away.
Dog Mouths Are Cleaner Than Human Mouths
Some of us may recall hearing this as kids, particularly if a dog licked your face or sampled whatever you were currently eating. “Don’t worry about it! Didn’t you know that a dog’s mouth is cleaner than yours?”
The idea that dogs’ mouths are clean was probably surmised by the fact that dogs lick their wounds and sometimes heal faster because of it. In reality, if a wound heals faster after a dog licks it, that’s because his rough tongue has been removing dead tissue and stimulating circulation, much like a surgeon would debride a wound. On the other hand, licking wounds can sometimes cause more harm than good by introducing bacteria and/or irritating the wound. Guess the people who came up with this myth did not consider the dog wounds that did not heal properly.
A dog’s mouth contains plenty of germs, not to mention other “icky” things. Think about the stuff your dog eats off the ground and out of the trash or the things he licks off of himself. Plus, many dogs do not get their teeth brushed as regularly as people, so there are the dental tartar and bacteria to consider (as if doggie breath didn’t give this away). Overall, a dog’s mouth contains more germs than anyone wants to think about. The good news is that these germs are usually dog-specific and unlikely to cause any harm to humans.
If you keep your dog healthy, dewormed and up-to-date on vaccines, there is little to worry over. Better yet, take care of your dog’s teeth and there’s even less going on in that mouth.
DOGS CAN SEE ONLY BLACK AND WHITE
It was once believed that dogs could see only in black and white (and shades of gray). Many people still think this is the case.
There is no evidence behind the origins of this myth, but it may have to do with old science. It could be that scientists came to the conclusion that dogs see in black and white before they fully understood the canine eye (or even the human eye for that matter) and the functions of cones.
Dogs can see color, but not the way most humans do. Based on the types of cones in the canine retina, dogs probably see colors best on the blue side of the spectrum. Canine color vision is thought to be similar to red-green colorblindness in humans, though not exactly the same. It is believed that dogs see primarily in blue, greenish-yellow, yellow and various shades of gray.
DOGS EATS GRASS TO MAKE THEMSELVES VOMIT
It’s true that dogs will often throw up after eating a lot of grass. This does not mean they ate that grass to induce vomiting, or that it is somehow a sign of illness.
The origin of this myth is most likely due to an incorrect assumption by dog owners. People observed their dogs vomiting after eating grass. They assumed that dogs intentionally ate grass when feeling sick to their stomachs in order to make them vomit. When you consider the real reason, this conclusion seems like the long way around.
Why do dogs eat grass? Probably because they simply like it. Some dogs like to graze while others chomp. Enough grass in the stomach can create minor irritation and cause the dog to vomit. Some experts believe that a dog’s taste for grass goes back to the days when a wild canid would eat the stomach contents of its prey (usual plants like grass and leaves). Regardless of the reason, it’s relatively harmless as long as the grass is not chemically treated. That being said, if grass-eating has led to chronic vomiting in your dog, you should probably keep him away from the grass and visit your vet just in case.
DOGS AGE SEVEN YEARS FOR EVERY HUMAN YEAR
Saying that a one-year-old dog is seven in dog years does not really make sense when you consider that dogs can reproduce well before one year of age. That would make 15-year-old dog 105 in dog years, which is not the case. Plenty of dogs live to 15 and are still healthy, active seniors (far more so than the humans who live past 100).
Someone probably looked at the average lifespan of people versus the average lifespan of dogs and made the estimate of seven dog years for every human year. It’s really just an over-simplified way of describing the rate at which a dog ages.
Dog’s age at a faster rate than humans, but that rate is faster early in life and seems to get slower with age. For instance, a one-year-old dog is basically like a human teenager, but an eight-year-old dog is like a middle-aged human (the latter matches up more closely with the seven-year theory). Most importantly, the size and breed of the dog have a lot to do with its aging rate and lifespan. Many small breeds are known to live 15 to 20 years while a lot of giant breeds only live 7 to 10 years. In a strange twist, young giant breed dogs tend to reach adulthood more slowly than the average dog, despite their shorter lifespans.