FIGURE 4-1 U.S. Department of Agriculture (USDA)-tracked animal use data for the United States, 1979 and 2009. (Data for rats, mice, birds, and cold-blooded vertebrates are not tracked.) NHP = non-human primate.
SOURCE: Yates presentation citing USDA Annual Reports.
Welfare Act. The UK Home Office tracks the number of procedures (not the number of animals used) and does include rodents. Over the past 20 years, the use of all animal species except mice has decreased (Figure 4-2).
Increased Use of Rodents
Prior to the mid-1980s, cats were popular research animals for classical neurophysiological procedures because they could withstand the extensive surgeries required, were large enough to accommodate bulky instrumentation, and were inexpensive models. However, in the mid-1980s, new regulations substantially increased the economic cost and administrative burden of feline models. In addition, public opinion shifted against the use of companion animals in research.
Miniaturization of instrumentation has allowed rodents to serve as replacements for felines in some studies. Refinement of techniques such