The 2023 Dog Days of Summer (July 3-August 11) have officially ended. Unfortunately, as explained in last year’s DYK the Dog Days of Summer Won’t Always Be in Summer, they have nothing to do with the calendar or the family pet. (Too bad, since if this summer’s brutal heat wave were a well-trained dog, we could order it to leave.) Since we can’t do anything about the heat, let’s talk about man’s best friend.

History

Dogs are descendants of wolves that were domesticated some 15,000-40,000 years ago. Those early dogs helped men hunt and acted as companion animals.

Did You Know…

• The Saluki, the oldest, still active, dog breed, dates back to 329 BC. Ancient Egyptian rulers kept them as royal pets. (In Southern Iraq, carvings of what appear to be a dog similar to a Saluki, date back to 7000 BC.)
• The first time “collie” was used in reference to a dog was around 1651. It is thought the word was a dialectal form of “Colley,” Coly,” or “Coaly,” which means “coal-black,” and likely referred to the black-faced sheep the dogs herded.
• In 1912, three dogs—two Pomeranians and one Pekingese, all belonging to first-class passengers—survived the sinking of the Titanic.

Senses

Puppies are born blind and deaf. At about two weeks old, their eyes and ears begin to open, though their eyes won’t fully develop for another eight weeks. A dog’s eyesight isn’t its strongest feature. Many are often near-sighted, and, while not color-blind, dogs see only shades and combinations of blue and yellow.

But a dog’s hearing is super sensitive. (Four times better than humans.) Eighteen ear muscles allow a dog’s ears to move in multiple directions, “tuning in” to the noises around them. They can hear soft sounds, meaning they can hear things far away. They also hear higher-frequency sounds. (Two times beyond a person’s hearing range.)

A dog’s sense of smell is also far superior to ours, and a female dog’s sense of smell is often better than a male’s. A dog’s wet nose—which is a sign of good health—helps absorb scent chemicals. A quick nose lick allows the dog to sample the scent, helping to identify it.

Did You Know…

• Adult dogs and wolves both have 42 teeth, ten more than humans.
• Dogs have three eyelids—the top, the bottom, and one on the side along the snout. This “nictitating eyelid” or “haw” keeps the eye protected and lubricated.
• Small dogs hear sounds in higher ranges than big dogs. In fact, the smaller a mammal’s head, the higher the frequencies it can hear.
• A dog’s nose has 100-300 million scent receptors—a human nose only has 5-6 million—and allows the dog to breathe while at the same time it sniffs and identifies a smell.
• The sound frequencies in thunderstorms can be painful to a dog’s ears.
• Dogs can be trained to smell cancer and other medical conditions in humans.

Physical

Dogs come in all sizes, shapes, and colors, but each has a nose print as unique as a fingerprint. And, as you can be right or left-handed, a dog can be right or left-pawed.

 Did You Know…

• A human yawn can trigger a dog yawn. If the human doing the yawning is someone known to the dog, it’s four times more likely the dog will yawn.
• Dogs have sweat glands only in their paws. They pant to cool down.
• The only two dog breeds with solid black tongues are the Chow Chow and the Shar-Pei. (No one knows why their tongues are black.)

Intelligence

Like people, some dogs can be smarter than others. An average dog can understand more than 165 words and gestures, while a smart one can learn 250 or more. They’re like a two-year-old, only easier to train.

Dogs can experience jealousy when they see their owner offering attention and affection to other animals, but they will also voluntarily share unselfish kindness with others, without expecting anything in return.

They can accurately interpret human emotions on people’s faces—whether in person or in a photograph—and respond appropriately. They can also smell emotions, especially fear.

Did You Know…

• Like humans, dogs have active dreams. Older dogs and puppies dream more often. While smaller dogs’ dreams are usually more vivid.
• In Russia, Moscow’s “metro dogs” (strays) have learned to ride a complex subway system. They know which trains to board and where to disembark to find food.

To Be Continued…