Chapter 2.11. Legal space requirement stipulations (2007)

LAREF [Laboratory Animal Refinement and Enrichment Forum]

Abstract

Is it indicated to push for larger than minimum-size standard cages? Individually caged animals have little or no use for extra space beyond the space required for free postural adjustments and a few normal steps/hops. Rather than exploring empty space, primates will climb up to a safe high corner of the enclosure and stay there, while rodents will show thigmotactic behavior, i.e., shunning the "unprotected" center but staying close to the walls of a barren enclosure, even if it is relatively large (Figure 6). The classical open field test (Hall and Ballachey, 1932) is based on this phenomenon: being exposed to an enclosed open area evokes anxiety. If I had to stay in a room for a long time, I certainly would prefer objects with which I can do something versus having access to another room that is completely empty. I assume that a monkey or a rat would show a similar preference to objects over more empty cage space.The current legal minimum space and exercise stipulations of the US Animal Welfare Regulations (United States Department of Agriculture, 2002) do not make it clear that the prescribed space must be structured in a species-appropriate manner so that the confined animals are encouraged to make use of it. It is easy to demonstrate "scientifically" that animals do not exercise or play, or benefit in any manner in a relatively large but empty enclosure (Hite et al., 1977; Bayne and McCully, 1989; Hughes et al., 1989; Line et al., 1989; Line et al., 1990a; Bebak and Beck, 1993; Crockett et al., 1993; Galef and Durlach, 1993; Crockett et al., 2000). To conclude from such findings that the animals do not need more than the minimum space required for free postural adjustment would be quite misleading. Legal space requirement specifications are insufficient as long as they only prescribe quantity of space, usually based on body weight, and fail to define quality of space.Yes, this is a crucial point. To concentrate too much on minimum space distracts from the real question, which is: What can the animal do with the space in the enclosure? More space, if not structured, will not do much to the welfare of animals in captivity. Any discussion on quantity of space needs be accompanied by a discussion on quality of space in order to be meaningful. Once you get beyond the minimum space needed by the animal for free movement and postural adjustments, the quality of space becomes much more important than the quantity of space. However, I have trouble when it comes to legislating quality of space. It would be rather impossible to write a legal document that could address each of the different species that are kept in research laboratories. I am not sure what the answer might be.Perhaps, experts of the various species can agree on basic space quality provisions that should be legally mandatory, for example: species-appropriate elevated resting surfaces for nonhuman primates, dogs, cats and birds, species-appropriate shelters for rats, hamsters, guinea pigs and amphibians, species-appropriate burrows for gerbils, species-appropriate nesting material for mice, straw/hay for rabbits, species-appropriate basking areas for reptiles. A good number of people do not need the law, telling them how to furnish the cages of the animals in their charge. I see the real problem in the fact that these people usually do not have the administrative power to implement their experience-based, often excellent ideas. Legal requirements are very important for them to give them some backing. Then there are other people who do not have the proper knowledge or do not really care. Here, professional guidelines and basic legal stipulations, defining the quality of cage space, would probably be helpful.I am sympathetic to the difficulties of adapting inflexible regulations to current circumstances. Unfortunately, however, animal welfare often takes a back seat to other concerns, and we are left with little option for refining traditional housing practices until the inspector shows up and says we have to.It would be a lot easier for us to improve the housing conditions for our animals if we had some legal regulations prescribing the quality of the enclosure space rather than just its minimum size.