For over eleven years, horses and humans have been cooperating in an unprecedented regular school bus service in the town of Vendargues in southern France. This service operates at the intracommunal level, collects over a hundred children each day at different stops in town and serves five different schools, using three different carriages. In addition, an original waste collection service is offered in the center of town. This service involves eight horses, five dedicated to the school bus service and two to waste collection. An additional back-up horse is kept as replacement in case of absence of one of the other horses. Our study is part of a monographic approach to the role of horses in Vendargues in their different jobs and occupations, along with their drivers and grooms. Based on an ethnographic study of co-working between horses and humans in this horse-drawn service, we seek to qualify the diversity of labor relationships. After exposing the theoretical and methodological framework of our research, we describe the actors, humans and horses, working every day in Vendargues as coworkers. We approach the work organization as a specific collective and/or team work. Finally, we propose to highlight the sustainability of this horse-drawn service as the result of setting the conditions that allow the emergence of an interspecific work collective, involving as partners both human and non-human collaborators.