Due to the phylogenetic relationship and close genetic and biological similarities with humans, non-human primates (NHP) are regularly used in biomedical and behavioural research. However, because of their highly developed cognitive abilities and social skills, the use of these animals in biomedical research is debated more and more. Although it is acknowledged that in specific research areas NHP are still essential, it is recognized that the use of these animals can only be done under strict conditions under the most optimal welfare aspects. Welfare aspects include housing conditions,...