Chapter 2 
Introduction 
This report assesses the state of the art and the 
potential for alternatives to using animals in three 
contexts: biomedical and behavioral research, test- 
ing of products for toxicity, and education. Dis- 
tinguishing among these three areas is important 
because both the patterns of animal use and the 
potential for alternatives vary among them. Re- 
search develops new knowledge and new technol- 
ogies; although prediction of results is one goal, 
unpredictable results may prove even more sig- 
nificant. Testing relies on standardized procedures 
that have been demonstrated to predict certain 
health effects in humans or animals. It entails the 
measurement of biological phenomena, such as 
the presence or absence of cancer or of skin irri- 
tation, or the concentration of certain substances 
in tissue or in bodily fluids. Education involves 
teaching students in the life sciences, health profes- 
sionals and preprofessionals, and research scien- 
tists, as well as the cultivation of humane attitudes 
toward animals at all levels. Alternatives in each 
of these three areas consist of procedures that re- 
place animals with nonanimal methods, that re- 
duce the number of animals used, or that refine 
existing protocols to make them more humane. 
In addition to evaluating alternatives in three 
areas, the assessment also examines ethical con- 
cerns regarding the use of animals, economic con- 
siderations of their use and the alternatives, funding 
for the development of alternatives, and current 
regulation of animal use. Most important, this re- 
port delineates seven major public policy issues 
(and associated options for congressional action) 
in relation to alternatives (see ch. 1). 
With a focus on the prospects for alternatives 
to animal use in research, testing, and education, 
this assessment necessarily excludes certain re- 
lated topics and treats others only in brief. The 
role of animals in food and fiber production falls 
outside the scope of this study, as does the role 
of animals in the commercial production of anti- 
bodies and other biological materials. In addition, 
OTA has not evaluated the use of animals for compan- 
ionship, sport, or entertainment. Although laboratory 
animals are an integral part of this assessment, OTA 
did not examine contemporary standards of their 
care (e.g., cage size, sanitation, ventilation, feeding, 
and watering). Lastly, the use of human subjects is 
not considered in this assessment. 
WHAT IS AN ANIMAL? 
In any biological definition of the word "animal,” 
all vertebrate and invertebrate organisms are in- 
cluded and plants and unicellular organisms are 
excluded. For the purposes of this report, how- 
ever, an “animal’' is defined as any member 
of the five classes of vertebrates (nonhuman 
mammals, birds, reptiles, amphibians, and 
fish). These five classes of vertebrates can be fur- 
ther divided into two major groups, cold-blooded 
vertebrates (reptiles, amphibians, and fish) and 
warm-blooded vertebrates (mammals and birds). 
Invertebrates, therefore, are not discussed as 
animals. 
Political and scientific discussions often incor- 
porate other subdivisions for the term "animal.” 
Although not strictly part of the definition in this 
report, the terms "lower” and "higher” are used 
in many discussions of alternatives that refine ex- 
isting animal procedures or that replace certain 
animal species with other ones. In these contexts, 
the substitution of “lower” animals for "higher” 
animals usually refers to using cold-blooded ver- 
tebrates instead of warm-blooded vertebrates. In 
addition, within the class of mammals, "lower” is 
generally used to designate, for example, rodents, 
while "higher” refers to primates, companion ani- 
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