The Active Territorial Defense Hypothesis (ATDH) and Passive Range Exclusion Hypothesis (PREH) are contrasted as possible explanations for patterns of latrine use in a high-density population of the European badger (Meles meles) in the United Kingdom. Using bait-marking techniques, temporal patterns in latrine use by individuals and social groups were investigated to test for any systematic marking behavior, especially whether coordination of individual actions might be involved in the group territorial marking strategy. Latrine use by 4 groups was concentrated primarily along territory boundaries and particularly along parts of the boundary closer to that group's sett, rather than closer to active feeding areas. Boundary latrines were used to a similar extent by each group, with a consistent percentage (but differing subset) of a group's boundary latrines used daily. Individually, badgers preferentially used certain latrines and male badgers, in particular, showed a tendency to deposit more feces in latrines closer to their group sett. Our results indicate that badgers partition the collective responsibility of marking their territories, with the result that their entire boundaries are marked regularly and consistently, regardless of where focal individuals may be feeding. Individuals did not simply defecate at the section of boundary closest to where they happened to be active, but rather according to a pattern resulting in comprehensive, regular group coverage of the border. The patterns of latrine use accorded more closely with the ATDH than the PREH. This study provides evidence that badgers may cooperate systematically to defend their territories.