Very little research has been done to verify these classifications of animal hoarding. However, in a review of a small number of cases, Reinisch10 classified 40% as overwhelmed caregivers, 20% as mission-driven hoarders, and 40% as exploiters.
Typical characteristics ofanimal hoarders
The majority of studies that examined the phenomenology of animal hoarding are detailed case reports prepared by animal control agencies and humane societies. In the two largest reports, the findings regarding sex and age were remarkably similar. Patronek4 reported that 76% of 54 hoarders were female, and nearly half of the 54 were 60 years or older. A report by the Hoarding of Animals Research Consortium (HARC) detailed 71 cases.7 Eighty-three percent of these cases were women; the average age was the mid-50s. Animal-hoarding behavior appears to develop in middle age or later, although research is lacking on this point.11 From half to nearly three-quarters of the individuals in these studies were single, widowed, or divorced. Interestingly, over half of the HARC sample lived with other individuals, including children and elders. Smaller case studies have reported similar sex and age distributions12,13; a recent Spanish study found a similar age distribution but a more equal sex representation.14
Most of the few studies on animal hoarding outside North America are case studies that document the existence of animal hoarding or describe the characteristics of hoarders within particular countries. For example, Svanberg15 reported media and government reaction to a Swedish woman who “rescued” 150 swans over several years by bringing up to 10 at a time to her one-room apartment. Also in Sweden, Zak16 described the case of a hoarder with 80 dogs, 1 cow, 2 pigs, 1 rabbit, and some poultry in unsatisfactory conditions, without any veterinary care. Other studies have detailed the condition of animals and characteristics of the owners in Spain, New South Wales, and Serbia14,17,18; these reports were similar to those from the US.
As noted, a recent study by Ockenden and colleagues12 in Australia found demographic similarities with US animal-hoarding cases, but the affected animals were in better condition than their American counterparts. To provide insight into the development of animal hoarding, Ramos and colleagues19 examined Brazilians who own large numbers of animals that are adequately cared for in normally functioning homes. These individuals showed more intense attachments to their pets than owners of just 1 or 2 animals; these types of attachments were suggested to be precursors to animal hoarding.
Types of animals most likelyto be hoarded
Details regarding the number and kinds of hoarded animals generally have been consistent across studies. Cats are the most frequently reported type of animal hoarded, followed by dogs, although in a study from Spain, there was a higher frequency of dogs than cats among the animal-hoarding cases.14 Farm animals and birds were also reported with some frequency (11% to 17% in some studies20). In the study by Patronek,4 in 35% of the cases, only a single species was hoarded; in 31% of the cases, 2 species were hoarded; and in 33% of the cases, more than 2 species were hoarded. Calvo and colleagues14 reported that 79% of cases involved a single species. The typical number of animals in these cases ranged from 10 to more than 900. Women were more likely than men to have more than 100 animals, and middle-aged persons (aged 50 to 64 years) had significantly more animals than did those who were younger or older.7
A comparison of animal and object hoarding outlined similarities, including a chronic course characterized by an exaggerated need to control, an exaggerated sense of responsibility, and intense emotional attachments to hoarded objects or animals.11 Both types of hoarding are also characterized by poor insight and great difficulty in parting with objects or animals. In both object hoarding and animal hoarding, the urge to save/acquire is intense, as is the distress when possessions are removed. A result of these behaviors is a seriously compromised living environment; in most cases, hoarding of animals results in more severe personal and public health consequences.
There are some notable differences between object and animal hoarding. In one study, most animal-hoarding cases involved squalid living conditions, while only a minority of object-hoarding cases did so.21 A review of the sex ratio indicates that it is relatively even for object hoarding, whereas animal hoarders are predominantly female.22 Although both conditions are characterized by poor insight, animal hoarders often exhibit delusional beliefs about special abilities to communicate with, understand, and care for animals.23
Dr Frost is Harold and Elsa Siipola Israel Professor or Psychology at Smith College, Northampton, Mass. Dr Patronek is Adjunct Assistant Professor at the Cummings School of Veterinary Medicine, Tufts University, North Grafton, Mass. Dr Arluke is Professor of Sociology at Northeastern University, Boston. Dr Steketee is Professor in the School of Social Work at Boston University. The authors report no conflicts of interest concerning the subject matter of this article.
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