1. Popularity contest
Like skirt length and baby names, certain dog breeds go in and out of fashion. Breed preferences also vary by region. Unfortunately, trendy dogs are as common in shelters as in homes. ASU animal psychologist Clive Wynne notes that Arizona shelters are currently crowded with Chihuahuas seeking forever homes.
2. The nose knows
Dogs are about 90 percent successful at finding chemicals we train them to find, such as explosives or drugs. Attempts to develop an artificial “nose” have only been about 50 percent successful.
3. But are they playing poker?
The oldest art depicting dogs is found in a cave painting in the Tassili n’Ajjer mountains in Algeria, from about 7-8,000 years ago. Wynne likes to claim that his dog Xephos is a direct descendent of the dog shown in the cave. “She looks just like the painting,” he jokes.
4. Best friends forever—or at least ten thousand years
No one knows exactly when humans domesticated dogs. Estimates range from 10,000 to 130,000 years ago. Differentiating ancient dog bones from ancient wolf bones is harder than it seems. Wynne notes that most ancient wolves were smaller than those that remain today, while small dogs are relatively modern. There wasn’t much of a size difference between the two animals thousands of years ago.
5. Dog. Food.
Unpleasant as it may seem, one of the reasons people may have wanted to domesticate dogs was to eat them. Eating dogs was common in Europe well into the 20th century, and it is still legal to eat them in Switzerland today.
6. Till death do us part
Human attachment to dogs is evident when people choose to be buried with their pups after death. The earliest known human-dog burial was discovered at Einan (or Eynan or Ain Mallaha) in Israel, dated to about 12,000 years ago.
7. Life in a landfill
Some of the densest populations of dogs live in landfills, like the Mexico City dump. In fact, more than 80 percent of the dogs on Earth today live as scavengers. Only a minority enjoys the pampered life of a pet.
8. Common ancestor
Wolves from the Negev Desert in Israel are the most likely ancestors of today’s dogs. These wolves are nocturnal and tend to scavenge among human trash.
9. Party personality
One particular genetic sequence, located near a gene called WBSCR17, differs greatly between dogs and wolves. In humans, the gene is involved in a disorder called Williams-Beuren syndrome. One of its symptoms is extreme gregariousness. Scientists speculate that a mutation in the wolf genome could have made some of the animals friendlier to humans and thus more attractive for domestication.
10. Pampered pups
Dog owners in the U.S. spent more than $53 billion on their canine companions in 2012, according to the American Pet Products Association.