A viral outbreak has apparently killed all land mammals. Human population spikes have forced countries to resort to somewhat drastic measures to control the human population. However, thanks to the deaths of most familiar animals, the governments had a better alternative than simply randomly killing citizens. Instead of killing them...they altered them. Used them to replace pets, to replace livestock. And for the last decade it had worked like a charm. So with that, raids continued and people, young, middle-aged and old, were all open to being captured and altered. Their brains were operated upon to decrease their intelligence and put them under the impression that they were animals. Tails and ears were standard for all, but depending on the types of animals they were made into, there would be more alterations. Dogs and cats were the most popular alterations, as the demand for pets had increased now that the technology had made it possible.
In the beginning anyone could be taken, if you were caught walking alone, even in day light, you could be taken and changed. Too many innocents were taken and the public outcry was enough to force the company to change its policy. The government would provide the pets. Those with debt, those who commit crimes or simply those with no ambition in a horribly over crowded world were taken and changed.
Occasionally private deals were brokered, a lender would forgive a debt in exchange for a pet. Taken while sleeping these pets often became the pampered pets of a wealthy lender. Pets became a currency, bribes for government officials and a sign of status. Many owners created harems of the altered pets.