Animal Welfare Information Center Newsletter, Spring 1996, Vol. 7 No. 1 *************************

Comparing Cage Space Requirements for Nonhuman Primates in the United States and in Europe

Viktor Reinhardt, D.V.M., Ph.D., Cathy Liss, and Christine Stevens,
Animal Welfare Institute, Washington, D.C.

Fifty-six investigators working closely with laboratory nonhuman primates were asked what they thought could be done to the home environment to improve their animals' well-being (1). The most frequent of 28 suggested recommendations was for larger cages (6). A comparison of cage space requirements in the United States (5, 10) with those in Europe (3) supports this recommendation. Table 1 lists the respective stipulations for animals up to 25 kilograms (kg) (Animals over 25 kg are considered only in the U.S. rules.).
[*ICON*] Table 1. Minimum cage space requirements for nonhuman primates in the United States (USDA 1991) and in Europe (EECC 19 86).

Minimum floor area for singly-caged primates is on average 44 percent smaller in the United States than in Europe. The difference is statistically significant (p<0.01) and ranges from -20 percent to -64 percent.

If a compatible cage mate is introduced, the floor area does not have to be enlarged in Europe. In the United States, however, it must be increased according to the companion's body weight. Supposing that paired partners have the same body weight, minimum floor area would have to be doubled in the United States but not in Europe. Under such a circumstance, pair-housed animals would be allocated 7 percent more floor space in the United States than in Europe. This difference is insignificant (p<0.01).

Minimum height requirements for single- or pair-housed primates are on average 22 percent lower in the United States than in Europe. The difference is significant (p<0.01) and ranges from +1 percent to -39 percent.

European rules recommend that perches be installed so that the animal (s) can utilize not only the horizontal but also the vertical space of the cage. U. S. rules recommend perches among other examples of environmental enrichment for providing means of expressing species-typical activities.

To: Introduction | Discussion | Conclusion | References


While floor area requirements for pair-housed nonhuman primates are similar in the United States and in Europe, floor area requirements for single-housed animals are markedly less in the United States than in Europe. Single-caging is the prevailing arrangement for primates in U.S. laboratories (6, 7). This implies that most animals are being kept in cages that are too small.
Figure 1. This 85-cm-high cage meets the European minimum requirements for primates of the body weight class 6-7 kg. It allows the installation of a perch, or other climbing surface, in such a way that an animal can normall y sit and walk not only on but also under it. The U.S. minimum requirements of 76-cm height do not fulfill this condition.

Minimal height requirements in Europe take the biological adaptation of nonhuman primates to a three-dimensional, arboreal environment (2, 4, 8, 9) into account by providing adequate space for the installation of a perch. The individual not only can normally sit and walk on the perch but also under the perch (fig. 1). Minimum U.S. height requirements do not meet this criterion in most instances. The perch has to be placed either too high, thereby not leaving enough leeway for normal balancing and posturing on it, or the perch has to be placed too low, thereby blocking part of the minimum floor area (fig. 2). Either situation is unacceptable.
Figure 2. This 77-cm-high cage meets the U.S. but not the European minimum requirements for prim ates of the body weight class 5-6 kg. The height of the cage does not permit installation of a perch without blocking part of the minimum floor area for normal sitting and walking. In the United States, a 77-cm-high cage is legal for animals weighing up to 10kg! In Europe, only animals weighing up to 3 kg could legally be housed in such a cage.

To: Introduction | Discussion | Conclusion | References


Minimum space requirements for caged nonhuman primates are subminimal in the United States when compared to Europe. The European space allocations are not perfect, but they may serve as an example of earnest intention to address the animals' spatial needs for species-typical locomotor behaviors, postures, and postural adjustments within the given constraints of cage confinement.

To: Introduction | Discussion | Conclusion | References


  1. Bayne, K. (1989). Resolving issues of psychological well-being and management of laboratory nonhuman primates. In Housing, Care, and Psychological Well-being of Captive and Laboratory Primates, E.F. Segal, ed., Noyes Publications: Park Ridge, NJ, p 27-39.

  2. Estrada, A. (1989). Comportamiento Animals Es Caso de los Primates. La Ciencia desde México, México.

  3. European Economic Community Council (1986). Directive 86/609 on the Approximation of Laws, Regulations, and Administrative Provisions Regarding the Protection of Animals Used for Experimental and Scientific Purposes. Journal Official des Communautes Européenes L358, December 18, 1986.

  4. Martin, R.D. (1990). Primate Origins and Evolution. A Phylogenetic Reconstruction. Princeton University Press: Princeton, N.J.

  5. National Institutes of Health (1985). Guide for the Care and Use of Laboratory Animals. NIH Publication No. 85-23, National Academy Press: Bethesda, Md.

  6. National Institutes of Health (1991). Nonhuman Primate Management Plan. Office of Animal Care and Use, NIH: Bethesda, Md.

  7. Reinhardt, V. (1994). Survey of environmental enhancement for research macaques. Laboratory Primate Newsletter 33(3): 1-2.

  8. Rose, M.D. (1974). Postural adaptations in New and Old World monkeys. In Primate Locomotion, F.A. Jenkins, ed., Academic Press: New York, pp. 201-222.

  9. Schultz, A.H. (1969). The Life of Primates. Universe Books: New York.

  10. United States Department of Agriculture (1991). Animal Welfare: Standards: Final Rule, Federal Register 56:6426-6505.

This article appeared in the Animal Welfare Information Center Newsletter, Volume 7, Number 1, Spring 1996

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