Pygmy marmosets, the world's smallest primates, are popular in both zoo exhibits and the illegal pet trade, with both contexts raising significant welfare concerns given their complex social and dietary needs.
Pygmy marmoset welfare in captivity is highly demanding to achieve. Their exudate diet cannot be fully replicated without providing gum-bearing substrates; commercial gum arabic is an incomplete substitute. UV lighting to prevent metabolic bone disease, high humidity replicating Amazonian conditions, and sufficient height for their arboreal lifestyle are all essential. Social isolation — common when kept as pets — causes extreme distress in animals that evolved in cooperatively caring family groups. Pet-trade pygmy marmosets are frequently obtained as infants through poaching, experiencing the trauma of maternal separation and long-distance transport. Their small size makes them appear manageable as pets; their welfare needs make them emphatically unsuitable outside expert zoo settings.