Research at Doñana Biological Station (EBD-CSIC) complies strictly with the EU legislation on the protection and welfare of animals used for scientific purposes. EBD-CSIC maintains a clear institutional policy about animal welfare based upon an ethical code of practice to which all researchers must adhere. According to this code, the use of living animals can only be justified if it seeks to benefit the animals themselves, the environment or the human beings. By adhering to this code, researchers make it sure that they will use animals only if there are no other feasible alternatives, that they limit use the number of animals used to a minimum, and that they will make every effort to minimize the negative impact caused to their welfare (3 Rs Principle). EBD-CSIC has its own Animal Welfare Body to oversee that specific research projects comply with legal requirements and adhere to the ethical code of practice.