Reinhardt, V. 2003. Legal loophole for subminimal floor area for caged macaques. Journal of Applied Animal Welfare Science 6(1), 53-56.

The USDA regulations pertaining to the minimum space requirements of nonhuman primates and the fitting of elevated resting surfaces are contradictory. They implicitly condone the prevailing perch design that allows maximal usage of animal room space by stacking the cages on top of each other but fails to address the animals' minimal spatial needs for normal postural adjustments with freedom of movement. An amendment to the regulations is needed to clarify that perches, ledges, swings, or other suspended fixtures have to be installed in such a way that they do not block part of the minimum floor space that is needed by an animal to make species-typical postural adjustments with freedom of movement.