According to this article
in the New York Times, there may be a biological basis for cat hoarding (not animal hoarding in general, but specifically cats). It cites the Centers for Disease Control talking about how the common parasite, toxoplasma gondii, may make us less sensitive to the smell of cat urine. Granted, it's a huge leap from not minding kitty pee to becoming a "crazy cat lady" or even a harmless multi-cat rescuer, like the murder victim in my first mystery, Mew is for Murder
. But as one Stanford researcher said, "The idea doesn't seem completely crazy."
Then again, this UCLA study
looks at the neurobiology of animal hoarders and finds that hoarders have significantly lower brain activity in the part of the brain known as the anterior cingulate gyrus. The study was looking at activity in that part of the brain for people with obsessive compulsive disorder, since hoarding has until now been seen as a manifestation of OCD. But hoarders had lower levels of activity there than other people who suffer from other forms of OCD. Therefore, the researchers concluded, hoarding may be more similar to age-related dementia – a finding that may aid treatment of compulsive "cat collectors." How did the researchers find all this out? A PET scan, of course.