@dogfacts

The Beatles song "A day in the Life" has an extra high-pitched whistle, audible only to dogs. It was recorded by Paul McCartney for the enjoyment of his Shetland sheepdog.

As an extra, here's a cool little doggo.

Puppies are born deaf and cannot hear until they are about 21 days old. The young are born small, blind and helpless and require a long period of parental care.

As an extra, here's a cool little doggo.

Female wolves have been known to travel great distances to regurgitate full meals for their hungry pups.

As an extra, here's a cool little doggo.

President Lyndon Johnson had two beagles named Him and Her.

As an extra, here's a cool little doggo.

Obesity is the top health problem among dogs.

As an extra, here's a cool little doggo.

Dogs don't enjoy being hugged as much as humans and other primates. Canines interpret putting a limb over another animal as a sign of dominance.

As an extra, here's a cool little doggo.

The U.S. has the highest dog population in the world.

As an extra, here's a cool little doggo.

The grief suffered after a pet dog dies can be the same as that experienced after the death of a person.

As an extra, here's a cool little doggo.

A puppy is born blind, deaf, and toothless.

As an extra, here's a cool little doggo.

Service dogs are recognized in the U.S. as "necessary medical equipment."

As an extra, here's a cool little doggo.

There are about 400 million dogs in the world.

As an extra, here's a cool little doggo.

A German Shepherd named Orient accompanied her blind owner Bill Irwin as he became the first blind person to through-hike the 2,100-mile Appalachian Trail in 1990.

As an extra, here's a cool little doggo.

While not the best when it comes to sight, dogs have a keen sense of hearing, and can hear sounds at 4 times the distance of humans.

As an extra, here's a cool little doggo.

Countess Karlotta Libenstein of Germany left approximately $106 million to her Alsatin, Gunther III, when she died in 1992.

As an extra, here's a cool little doggo.

Dogs DO have better low-light vision than humans because of a special light-reflecting layer behind their retinas.

As an extra, here's a cool little doggo.