SUMMARY
The backyard animals have an important role in the life of the communities, since they provide animal protein for ingestion as well as to obtain economic income when selling them or they simply fulfill an aesthetic or emotional function. The presence and permanence of these animals implies the development of certain practices in feeding, care and health. Ethnoveterinary Medicine (MEV) provides knowledge of use, management and maintenance of the health of backyard animals. The objective of the present study was to analyze the sociocultural, economic, biological and inter-animal interactions between human beings and backyard animals within the MEV.The study was conducted in two communities of Tabasco State: one of them peri-urban (Ranchería Guineo Segunda Sección) and the other a rural one of Chontal indigenous population (Tucta, Nacajuca). Methodology was undertaken in two distinct moments: during the first one, semi-structured interviews were applied; in the second one, after treatments data systematization was accomplished, workshops were conducted in order to corroborate and to enrich the information. A total of 85 treatments for a number of animal diseases were found in both communities, which are utilized on livestock, companion animals such as dogs, and mainly on domestic fowl: local chickens and ducks, commercial-line chickens and laying hens. A close relationship was found among the interactions of human beings with their backyard animals, along with a wide number of EVM practices for the preservation of health in the animals. From the wide assortment of resources utilized on the recorded EVM practices, and according to the literature, 73 % are part of the traditional medicine applied for human beings in México, 19% in MEV and 8% use in other topics.We conclude that the practices of the MEV contribute to the strengthening of the interactions; a) interannality: the human being as a member in the animal kingdom interacts with his backyard animals, the how and under what conditions of this interaction can determine the ethical treatment that they are given; b) biological: in doing use and management of natural resources of their environment for treatments and ensure the permanence of native breeds as they respond better to the environmental conditions of each area and the MEV; c) economic treatments: compared with conventional treatments are cheaper even for free , as well as savings in facilities or specialized food compared to introduced breeds. Finally, d) sociocultural: the interactions that arise between members of the communities when exchanging knowledge of the MEV and the role that the animals have for certain cultural rituals.