Most people know that a Russian mongrel named Laika made the first “manned” space flight (in 1957). But few people know how many dogs actually went into space and how many made it back. In all, 13 dogs flew on Russian spacecraft; 5 never made it back, including Laika.

Of all the dogs that made space flights, only Laika was actually sent aloft with the knowledge that there was no way she would ever be recovered. The dog’s plight captured the hearts of millions around the world as her life support systems wound down. The American press dubbed the dog “Muttnik.” In 1997, Russia dedicated a memorial to the fallen dog hero.

A greyhound can run up to 45 miles an hour in a short dash. That’s just 15 miles an hour slower than the speed of the cheetah, the fastest animal on earth. (A cheetah can run 60 miles an hour. Here’s an interesting fact about cheetahs: they don’t stalk like cats; they run down their prey like dogs. 

In a dog, the nose knows more quickly than the other senses. While humans have to be content with a mere 5 million to 20 million scent-sensitive cells, most dogs boast between 120 million and 200 million of these cells. Bloodhounds have the best sniffers of all – more than 300 million scent cells line the nostrils of these dogs.

Right behind a dog’s nose sense is his sense of hearing. Again, your dog’s hearing abilities put yours to shame. Human beings can hear sound waves of up to 20,000 cycles per second (sound waves). A dog can hear up to 100,000 cycles per second. Filters within the ear enable your dog to distinguish the far-away sound of your car. This is why he pricks his ears up while the rest of your family is unaware of your imminent arrival.

Although a dog has a vastly superior nose, he has decidedly inferior taste buds. Compared to a person, who has almost 10,000 taste buds, a dog makes do with only a few hundred. In other words, dogs cannot tell many tastes apart. The enjoyment of food comes primarily from the aroma. In addition, a dog is genetically wired to gorge, especially if there’s another dog around, because in the wild dogs never knew when their next meal was coming.

Although a dog has a vastly superior nose, he has decidedly inferior taste buds. Compared to a person, who has almost 10,000 taste buds, a dog makes do with only a few hundred. In other words, dogs cannot tell many tastes apart. The enjoyment of food comes primarily from the aroma. In addition, a dog is genetically wired to gorge, especially if there’s another dog around, because in the wild dogs never knew when their next meal was coming.

Your dog’s heart is similar to your own. It is divided into four chambers: the right atrium and ventricle channel blood to the lungs to get oxygen while the left atrium and ventricle pump the blood to the body. But unlike you, your dog has very little chance of suffering a heart attack or stroke.

Unfortunately, dogs do suffer from other common ailments found in people, such as diabetes and cancer. One common disorder is congestive heart failure – which means the heart muscle cannot pump blood efficiently. (Heart failure is not the same thing as a heart attack, in which the heart muscle begins to die because of obstruction of circulation to the area) Congestive heart failure is in the top five illnesses for which veterinary treatment is required.

Dogs often get conjunctivitis – otherwise known as “pink eye” – and their owners worry that the infection can be passed on to the human family members. Relax. The bacteria that causes conjunctivitis in dogs is not the same as the one that affects humans.

People sometimes consider their dogs to be almost human. That’s fine when it comes to showering affection and attention on your pet, but dangerous if you try to give him human medication. Dogs should never be given over-the-counter medication, unless specifically prescribed by a veterinarian. For instance, if aspirin is given incorrectly it can cause stomach bleeding in dogs.

North America has the highest population of dogs in the world. The Chihuahua is believed to be the oldest breed of dog native to the North America. It hails from the Mexican region of the same name.