Dogs in general are prizes for theirfaithfulness and eagerness to please’ these qualities, among with their playfulness, trainability , downright liability, have earned the dog title o Man’s best friend. In fact, no other bond between species is as widespread between people and dogs.

According to the latest Nation Pet  Survey, Americans own 83 million dogs. Over the 46 percent  American household have at least one dog.

The traits that make dogs excellent pets also qualify them as a valuable service animal for the disabled and therapists for hospital patients, autistic children and traumatized veterans. While some dogs perform serious tasks and demonstrating their obedience, agility and good looks at dogs shows and competitions.

All dogs are descended from wolves that were domesticated  about 15,000 years ago. For thousands of years , dogs were bred fpr certain skills, such as flushing out and retrieving game for hunters or killing rodents. But in the late 1800s, people began breeding  primarily for appearance and relatively few generations, developed completely new breeds. Thanks to human tinkering with canine DNA, dogs now exhibit the greatest variation in size and appearance of any animal.

For 21 years, the Labrador  retriever has remained top dog in the  United States. Although the beagle, bulldog and Rottweiler have moved up in popularity. While some breeds such as Yorkshire terriers and dachshunds are perennial favorites. Americans generally prefer larger dogs. According to American kennel Club registrations in 2013, the 10 most popular breeds were:

1.       Labrador retriever

2.       German shepherd

3.        Golden retriever

4.       Beagle

5.       Bulldog

6.       Yorkshire terrier

7.       Boxer

8.       Poodle

9.       Rottweiler

10.   Dachshund

In  addition to these standard breeds, designer dog breeds or hybrid dogs are trend in the United States. New breed combinations such as labradoodles(Labrador retriever and poodle), cockapoos (cocker  spaniel and poodle) and puggles (pug and beagle) are  high demand.

With their superior sense of small and hearing and their eagerness to please, dogs are well-suited to a variety of important task, such as sniffing out drugs, bombs, land mines and locating victims of natural or man-made disasters. A group called Working dogs for conservation trains dogs to follow the scents of elusive wildlife, locate endangered species and indentify rare or invasive plants.

Dogs provide emotional benefits as well. People with animal companions tend to be less lonely and to have higher self-esteem. Some psychologists maintain that the benefits people gain from interactions with pets can be equal to those from friendship with another person.

Although so-called seeing-eye dogs trained to guide the visually impaired are the best known service animals. Dogs also provide various  kinds of assistance.

Hearing dogs alter people who are deaf or hearing impaired to important sounds such as doorbells, smoke alarm, telephones and alarm clocks.

Mobility assistance dogs aid the physically disabled by picking up object , opening doors and operating light switches.

Medical response dogs can carry life support equipment,  such as oxygen tank and warn people about certain medical situations before they occur.

Autism service dogs can accompany autistic children to school, where they provide a calming influence and  a focus for the child that promotes better interaction with classmates.

Psychiatric service dogs aid people with condition such as schizophrenia, the dog can guide a person  who becomes disoriented, retrieve medication, interrupt repetitive obsessive behavior .

All type of assistance dogs typically wear vests indentifying them as service animals. Under  the American with Disabilities act, service animals are allowed to go any where the public goes, including business, restaurants, theaters and transit systems.