Although theories of domestication have suggested that dogs evolved a greater capacity for tolerant and cooperative behaviour compared to their wild wolf cousins, the differences between wolves" and free-ranging dogs" social ecology, with wolves relying more on conspecific cooperation than dogs, would rather predict the opposite. In a cooperative task involving joint action on a rope to pull a tray forward, wolves systematically outperformed dogs. The dogs" failure appeared largely due to tolerance issues, i.e. one partner avoiding interacting with the apparatus, when the other was engaged with it, rather than cognitive limitations. To verify this, in the current study we trained the dominant partner to become an "expert" on the task thereby potentially enhancing their understanding that they "needed the partner to succeed". Indeed both the duration of co-action on the apparatus and the success rate of dyads composed of an expert and an inexperienced dog was higher than dyads composed of two inexperienced partners. Nevertheless the dogs" performance was substantially poorer than that of wolf dyads with equivalent experience, highlighting that despite the facilitating effect of the "expert", cooperation on this task did not come easily to dogs. For both dogs and wolves, cooperation was facilitated by the closeness of the affiliative bond between individuals, but opposite rank effects emerged. Dogs further apart in rank were more successful co-operators, whereas in wolves, animals closer in rank had a higher cooperative success. The results further highlight the importance of the different socio-ecologies of wolves and dogs in understanding their behaviour.