Before animal shelters, there were pounds, used to contain wandering livestock until they could be recovered by the owner. They had to pay a fee to the poundmaster first though. Livestock was valuable, so it was usually reclaimed, but dogs and cats had little monetary value and were often killed. In 1866, the American Society for the Prevention of Cruelty to Animals (ASPCA) was founded, which is the first animal welfare organization in the USA. But at the time, they only focused on the treatment of horses, not dogs and cats. In 1866, the purpose of animal shelters was not to give refuge to lost pets, but to keep the public safe and provide a “humane” death for the animals. This continued until the 1970’s, then veterinary input was used to make a better environment for the pets.
Today, over 5,000 animals shelters exist in the United States, as estimated by the ASPCA. These shelters take care of the animals in their care, and sometimes offer obedience classes and other things. There are two types of shelters: municipal and private. Municipal shelters are under municipal control and are funded by taxes and money from dog licences, etc. Private shelters are non profit organizations that receive their funds from fundraisers, etc. The thing that changed animal shelters drastically was the no-kill movement that started in San Francisco in 1989, lead by Richard Avanzino. There were many arguments about how enthusia was used as the main form of animal control. These days there are other forms of animal control, such as spaying/neutering pets, and adopting found pets instead of killing them.
While animals shelters have evolved over time, there is always room for improvement.