When wild animals were domesticated?

   Scientists believe that humans began to tame animals some 12,000 years ago. At that time, people obtained food largely by hunting animals. Wolves probably followed the hunters, searching for meat the humans left behind. It's possible that one day a child looking for firewood stumbled across an orphaned wolf pup. The child might have taken the pup home and raised it as a pet. Over time, other wolves must have begun to live with humans.
   That's how the whole process of domestication might have started. When the tame wolves had pups, people would have kept those they liked best: the biggest pups or the smallest, the strongest ones the friendliest ones, or the ones with the curliest tails.
   After many generations of being tamed and bred, the wolves became domesticated. Many of them no longer looked much like their ancestors. Some were bigger. Some were smaller. Many had fur colors quite different from those of wolves.
   By choosing and breeding early wolf-dogs with cer­tain characteristics, humans created many breeds of dogs. Today there are about 150. Many scientists say all dog breeds—from delicate Chihuahuas to wolflike huskies—are descendants of the wolf. Others believe another doglike animal, now extinct, is the ancestor of many breeds.
   The wolf was probably the first animal to be domes­ticated. After wolves, people adopted many other ani­mal companions. The newest addition to households is the gerbil—domesticated only 50 years ago.
   A number of the animals people often enjoy as pets today probably started out not as people's companions but as handy meals. From studying bones uncovered in ancient dwellings, scientists know that horses were once an important source of food for humans. Old handwritten books tell of monks raising rabbits to eat on certain religious days. And, of course, people still raise cattle, chickens, and other animals for food.
Along the way, an especially warm bond developed between certain kinds of animals and their owners. These animals were so intelligent, friendly, loyal, or useful that people began to have second thoughts about eating them. These animals became pets.
   Most pets have one thing in common: Their relatives in the wild live in groups. Wolves live in packs, horses and guinea pigs run in herds, goldfish swim in schools, and parrots fly in flocks. These animals were accustomed to companionship, so people found it easy to tame them. The animals transferred their loyalty from their group leaders to their new masters.
   Not all pets of today once lived in groups, however. The ancestor of one familiar pet, the cat, has always lived and hunted alone. It's called the African wildcat.
   Cats were first domesticated in Egypt, about 4,000 years ago. At that time, historians believe, African wildcats learned that villages were good places to catch mice and other rodents. At first, the cats hunted outside. Then they began to slip into houses. Happy to be rid of rodents, people probably welcomed the cats, and adopted orphaned kittens.
   The new partnership grew. Today, there are millions of cat owners. Does it sometimes seem that cats think they are the owners, and people their guests?