Apparatus for shielding a non-human animal from a sterilizant. The apparatus (100, 200) defines a space (102, 202) for accommodating a non-human animal (111, 204) and a shield (107, 201) for shielding a part of the animal from a sterilizant such as radiation. Only exposing a specific part of the animal to sterilizant produces a sterile animal which is better adapted to mate with other animals. When the sterilized animals are released in a sterile insect technique, the technique is more efficient because the released animals are better adapted to mate with a wild population.