Earlier this year, ASPCA Humane Law Enforcement Agents arrived at a New York City apartment to find that dozens of cats and kittens had overtaken the small space. The cats were severely malnourished, and many suffered from upper respiratory disease. There were no litter boxes, and the floor was covered in several inches of feces and urine. Living among the filth and debris was an 85-year-old woman suffering from dementia—she had been hoarding animals for years.

Animal hoarding is a complex and intricate social issue with far-reaching effects that encompass mental health, animal welfare and public safety concerns. Victims can include cats, dogs, reptiles, rodents, birds, exotics and even farm animals. While it’s not clear why people become animal hoarders, current research suggests the cause is often attachment disorder in conjunction with personality disorders, paranoia, dementia, depression and other mental illness. The hoarder does not intend to inflict harm on animals, and in most cases, the hoarder can no longer take care of himself, much less multiple animals.