Non-human primates used in research have complex social and cognitive needs. Their use raises acute ethical questions, and welfare standards must be rigorously applied when their use is justified.
Non-human primates experience some of the most significant welfare harms of any laboratory animal due to their cognitive sophistication and complex social needs. Historical practices of single housing in barren cages caused severe psychological harm — self-injurious behaviour, stereotypies, and depression. Modern welfare standards require social housing, environmental enrichment, and positive reinforcement training to reduce handling stress. Even with best practice welfare, the confinement and experimental use of highly intelligent, socially complex animals remains ethically contested. The 3Rs principle of Replacement demands that alternatives — in vitro models, organoids, imaging studies, and computational approaches — be prioritised and developed to reduce primate research over time. Where primate research is judged scientifically necessary, the highest possible welfare standards must be applied rigorously.