Figure 2. This 77-cm-high cage meets the U.S. but not the European minimum requirements for primates of the body weight class 5-6 kg. The height of the cage does not permit installation of a perch without blocking part of the minimum floor area for normal sitting and walking. In the United States, a 77-cm-high cage is legal for animals weighing up to 10kg! In Europe, only animals weighing up to 3 kg could legally be housed in such a cage.
Reinhardt, Viktor; Liss, Cathy; Stevens, Christine. "Comparing Cage Space Requirements for Nonhuman Primates in the United States and in Europe," Animal Welfare Information Center Newsletter, 7(1):12-13, Spring 1996.