The blood of the Koala (Phascolarctos cinereus)

Abstract

Blood counts were performed on 47 specimens of Phascolarctos cinereus, a marsupial commonly known as the koala or native bear which lives exclusively on a diet of eucalyptus leaves, and the results were subdivided into "normal", "abnormal", and "doubtful". Compared with man, the average normal haemoglobin was low (12.9 g/100 ml). Nucleated erythrocytes were practically always present as well as reticulocytes. Lymphocytes were more numerous than neutrophils. In injured or infected animals, neutrophils were more numerous than lymphocytes and reticulocytes and nucleated erythrocytes were frequently absent. In blood dyscrasias, however, the latter were usually numerous. These two groups provided the abnormal results. In the absence of definite clinical signs a considerable group of koalas exhibited deviations from the assumed normal blood picture. These deviations were usually slight and the results were referred to as doubtful.