Guidelines and legal codes for the welfare of non-human primates in biomedical research.

Recommendations have been drawn up in different countries for the housing of non-human primates. Four of them are compared and it is clear that there is little consistency with regard to spatial allowances or suitable temperature and humidity ranges. Often the cage sizes quoted are incompatible with requirements to meet the behavioural needs of the animals. Only one provides guidance on primates' different social needs. To achieve greater consistency and credibility, guidelines should be regularly revised to include advances in our knowledge of the animals' needs.