According to the Humane Society of the United States, 3–4 million dogs and cats are euthanized each year in the United States and many more are confined to cages in shelters because there are many more animals than there are homes. Spaying or castrating dogs helps keep overpopulation down. Local humane societies, SPCAs, and other animal protection organizations urge people to neuter their pets and to adopt animals from shelters instead of purchasing them.
"I like to give my clients options, options that give them more of a comfortable feeling when trusting there beloved pet in the hands of a complete stranger. My dog was a rescue, she felt more comfortable at home or with me than anything else. Being in someone's home with out me present or being caged would sky rocket her anxiety through the roof. Many pet owners can agree that a pet is not just a pet but like an actual part of the family. For pet owners that have pets such as mine I do like to provide them the option of in home services to ensure there pets are as comfortable as possible while they are away. Services provided include walking, daily meals, bathing, medication administration, house/pet sitting, in home boarding, boarding in my own home, lots of fun and play time as well. Whatever your comfortable with it can be provided. Animal care has been my passion sense I was a little girl. Taking care of animals is not just a way to earn a quick buck for me, I actually enjoy it."
There are many different shapes for dog tails: straight, straight up, sickle, curled, or cork-screw. As with many canids, one of the primary functions of a dog's tail is to communicate their emotional state, which can be important in getting along with others. In some hunting dogs, however, the tail is traditionally docked to avoid injuries. In some breeds, such as the Braque du Bourbonnais, puppies can be born with a short tail or no tail at all.
A common breeding practice for pet dogs is mating between close relatives (e.g. between half- and full siblings). Inbreeding depression is considered to be due largely to the expression of homozygous deleterious recessive mutations. Outcrossing between unrelated individuals, including dogs of different breeds, results in the beneficial masking of deleterious recessive mutations in progeny.
Wolves kill dogs wherever they are found together. One study reported that in Wisconsin in 1999 more compensation had been paid for losses due to wolves taking dogs than for wolves taking livestock. In Wisconsin wolves will often kill hunting dogs, possibly because the dogs are in the wolf's territory. A strategy has been reported in Russia where one wolf lures a dog into heavy brush where another wolf waits in ambush. In some instances, wolves have displayed an uncharacteristic fearlessness of humans and buildings when attacking dogs, to the extent that they have to be beaten off or killed. Although the numbers of dogs killed each year are relatively low, it induces a fear of wolves entering villages and farmyards to take dogs, and losses of dogs to wolves has led to demands for more liberal wolf hunting regulations.
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The dogs' value to early human hunter-gatherers led to them quickly becoming ubiquitous across world cultures. Dogs perform many roles for people, such as hunting, herding, pulling loads, protection, assisting police and military, companionship, and, more recently, aiding handicapped individuals. This influence on human society has given them the nickname "man's best friend" in the Western world. In some cultures, however, dogs are also a source of meat.
In 2013, an estimate of the global dog population was 987 million. Although it is said that the "dog is man's best friend", this refers largely to the ~20% of dogs that live in developed countries. In the developing world, dogs are more commonly feral or communally owned, with pet dogs uncommon. Most of these dogs live their lives as scavengers and have never been owned by humans, with one study showing their most common response when approached by strangers is to run away (52%) or respond aggressively (11%). Little is known about these dogs, or the dogs in developed countries that are feral, stray or are in shelters, because the great majority of modern research on dog cognition has focused on pet dogs living in human homes.