Based on an article that first appeared at

Do you think you know everything there is to know about canines? Think again! Check out these 23 interesting facts you may have never heard:

  1. Dogs have a sense of time. They know the difference between an hour and five. If conditioned, they can predict events, such as regular walk time.

    Dog telling time
  2. Your dog is as smart as a two-year-old! Children around this age share a special bond with dogs because they both understand roughly 250 words and gestures.

    Dog as smart as a 2-year-old
  3. A study at UCSD claims that your dog can genuinely get jealous when they see you display affection for another creature.

    Jealous dog
  4. The United States has the highest pet dog population in the world—approximately 75.8 million.

    Dog population in the US
  5. Seeing eye dogs are trained to do their “business” on command to make cleanup easier. Popular commands include “get busy” and “go time.”

    Service dog potty training
  6. Petting a dog and gazing into their eyes releases oxytocin (the “love hormone”) for both of you.

    Petting a dog
  7. The Saluki is the world’s oldest dog breed, appearing in Egyptian tombs dating back to 2100 B.C.

    Ancient Egyptian dog
  8. Dachshunds were originally bred to fight badgers.

    Dachshund dog
  9. Dogs that have been spayed or neutered live longer than intact dogs.

    Older neutered dog
  10. More than half of all U.S. presidents have owned dogs.

    Presidential dogs
  11. Stray dogs in Russia have learned to ride the subway and get off at specific stops in search of food.

    Russian subway dog
  12. Your dog can smell your feelings. Dogs detect sweat changes when humans are fearful.

    Dog smelling emotions
  13. Dogs have wet noses because it helps absorb scent chemicals.

    Dog with wet nose
  14. Dogs can be trained to detect cancer and other diseases. Cancer cells release distinct metabolic waste products dogs can smell.

    Dog detecting cancer
  15. Dogs with separation anxiety may be comforted by clothing that smells like their owner.

    Dog with owner's clothing
  16. Dogs prefer to poop aligned with the Earth’s magnetic field.

    Dog pooping
  17. Dogs curl up in a ball when sleeping to keep warm and protect vital organs.

    Curled up dog sleeping
  18. Having a dog can improve dating chances. In one study, men’s chances of getting a phone number rose from 10% to 33% with a dog present.

    Dog helping people date
  19. Labradors have been the most popular breed in the U.S. for the last 26 years.

    Labrador retriever
  20. There are about 600 million dogs worldwide, with nearly 400 million estimated to be strays.

    Stray dogs
  21. Scientists believe the first known dog lived 31,700 years ago, resembling a large Siberian Husky.

    Ancient husky dog
  22. Former Michael Vick dogs, Sox and Hector, became certified therapy dogs and now cheer people up in hospitals, nursing homes, and schools.

    Michael Vick's dogs turned therapy dogs

    Credit: Modern Dog Magazine

  23. Spiked collars were originally fashioned in ancient Greece to protect dogs’ throats from wolf attacks.

    Spiked dog collar