Almost 3 million dogs and cats that are otherwise healthy and adoptable and in need of "forever" homes are euthanized every year in the United States. Shelters frequently overrun with residents, dispatch animals that are not only in good physical condition, but have dispositions that make for great pets. These include purebred, mixed breeds, and animals of unknown heritages. Although pets and would-be pets that meet such an untimely demise may represent some animals that are lost and never picked up or returned, they also include the offspring of many family pets. Unfortunately, people are simply irresponsible and fail to neuter their dogs and cats for myriad of mostly uniformed reasons.
When I lived in Southern California, I used to take my rescued doberman to Los Angeles' Griffith Park Dog Park. I was shocked at how many people would bring intact male dogs into the enclosed off-leash facility. I can't speak to how many unaltered females were brought in, but I'm sure there were plenty. I was most presumptuous in thinking that people who cared enough to exercise and socialize their dogs, regardless of their socioeconomic background, would be very informed and responsible pet owners. But even among people compassionate enough to rescue dogs there are those who continue to perpetuate the pet overpopulation crisis.