Micrococci are obligate aerobic cocci, which after 24 h of incubation on blood agar grow as large pigmented colonies. They utilize carbohydrates oxidatively, but in general, they utilize far fewer carbohydrates than staphylococci. In the microscope, they are grouped as pairs or grapes. They can be isolated from a wide range of animal species worldwide, but they are not known to have any serious impact on laboratory animals. Different Micrococcus species are identified based on the reactions given in Table 11.1. The use of the commercial kit API STAPH (bioMérieux, France) also leads to an identification of micrococci.