Decades of great ape cognition research have revealed mental capabilities — theory of mind, culture, language learning, and planning — that profoundly challenge the human-animal boundary and have direct implications for great ape welfare and legal status.
Great ape cognitive research has been conducted partly in captivity using research institutions, zoos, and field sites. The evidence accumulated demands that captive great apes be housed in large, socially complex environments with cognitive enrichment proportional to their capabilities. The same research that demonstrates great ape cognition also provides the ethical case for their legal standing beyond property status — a debate actively pursued in courts in several countries through the Non-Human Rights Project.