The American Society for the Prevention of Cruelty to Animals (ASPCA)

The ASPCA is one of the most active pro-pet groups in the world. A nonprofit company, the ASPCA sponsors countless numbers of groups and events to protect animals' and pet owners' rights. The ASPCA has attempted to reduce pain, fear, and suffering in animals through humane law enforcement, legislative advocacy, education, and hands-on animal care.

The ASPCA was founded in 1866 by a diplomat named Henry Bergh, who served in the U.S. delegation to Russia. Bergh modeled the ASPCA on England's Royal SPCA. The ASPCA managed to get the nation's first anti-cruelty laws passed in the state of New York in its first year. The ASPCA provided ambulance service to horses in New York City two years before the first hospital provided them for humans. In seven short years, twenty-five states, a number of territories, and Canada had used the ASPCA as a model for their own humane organizations.

Today, the ASPCA supplies a number of different services to pet and animal lovers all across the country. They are perhaps best known for helping shelter strays and foster adoptions. Their foster care program encourages sympathetic people to help animals who are “too young, sick, or aggressive to be offered for adoption right away a chance to have a long and healthy life by placing them in temporary homes.”

People often confuse the New York-based ASPCA with other SPCAs around the country. There are Societies for the Prevention of Cruelty to Animals (SPCAs) in many states. The Massachusetts and San Francisco SPCAs are particularly active in promoting animal welfare through adoption and public education.

The Humane Society of the United States (HSUS)

The Humane Society of the United States (HSUS) is another of the nation's largest animal-protection organizations. While the ASPCA is more focused on pets, especially dogs and cats, the Humane Society has a much wider scope. HSUS promotes the “humane treatment of animals and to foster respect, understanding, and compassion for all creatures.” The HSUS uses such venues as the legal system, education, and legislation to ensure the protection of animals of all kinds.

The HSUS was founded in 1954 and currently has nine major offices in the United States. Unlike the ASPCA, the HSUS does not have any affiliate shelters. The HSUS mainly concerns itself with wildlife protection, companion animals, and animal research violations. However, they do sponsor many events for pet owners and do encourage pet rescue (adoption). Some of the events they sponsor include free spaying clinics for pet owners of insufficient means.

The American Humane Association (AHA)

Based in Englewood, Colorado, and founded in 1877, the American Humane Association (AHA) is a welfare organization involved in assisting both animals and children. These days the AHA oversees the treatment of animals on movie and television sets and is working to establish standards for dog trainers, among many other things.

Delta Society

The Delta Society was established in 1977 in Portland, Oregon, under the leadership of Michael McCulloch, MD. The organization's first president was Leo K. Bustad, DVM, PhD, dean of a veterinary college and a pioneer in human-animal bond theory and application. From the beginning, Delta has sought to better understand why animals are important to the general population and specifically how they affect health and well-being. Delta provided the first comprehensive training in animal-assisted activities and therapy to volunteers and health care professionals, and it continues to develop standards-based training materials. It is committed to its mission to improve human health through service and therapy animals.

Therapy Dogs International (TDI)

Elaine Smith founded TDI in 1976 to create an organization dedicated to regulating, testing, and registering therapy dogs as well as their handlers. Through this process, they are better prepared and able to assist in visits to nursing homes, hospitals, and other institutions where therapy dogs are needed.