In 1838, after months of investigation, a group of buffalo thieves was apprehended in the mountains of northern Vietnam. Due to legal statutes that defined buffalo as assets, imperial authorities ordered the public execution of the group’s leader, Đinh Công Tử, whose head was later displayed outside the villages most affected by buffalo theft. This presentation considers the legal lives of buffalo in northern Vietnam during the nineteenth century. Under both the autonomous Nguyễn dynasty (1802-1885) and French protectorate rule (1885-mid 1940s), buffalo received legal protections as biotic farm machines, despite their more complex socio-cultural roles in rituals and religious traditions. Buffalo crime and buffalo-related punishments index the importance of buffalo as engines of agricultural expansion. For both the Nguyễn and French periods, punishments for buffalo theft, including from public lashings and decapitation by the imperial authorities and, eventually, incarceration under the French, enable historians to track the unexpected ways that imperial and colonial subjects frustrated official attempts to promote sedentary agriculture.