106 | Cats Domestic felines come in many shapes and sizes, including the nearly hairless Sphynx They are used in a variety of laboratory experiments (Photos.com) Research in these areas is contributing to both feline and human health Compared to other nonhuman animals, the numbers of cats used for biomedical research is small and continues to decline In 1995, fewer than 30,000 cats were used for research purposes in the United States, representing only two percent of all research animals used that year, excluding rats and mice At present, cats reportedly comprise less than one percent of all animals used in research Furthermore, the institutions conducting research with cats in the United States, Great Britain, and many other countries must comply with strict regulations for animal care and use specified by their respective animal welfare laws An issue of even greater concern is the ongoing problem of cat overpopulation, particularly the problem of freeroaming, unowned, feral cats Although the number of such cats is difficult to determine, estimates of their numbers is as high as 70 million across the United States Several factors may account for the existence of so many homeless cats First, many people believe that cats can survive easily on their own and choose to abandon their pets when it is inconvenient to keep them Also, pet cats with access to the outdoors sometimes stray