Seasonal Effects on the Hematology and Blood-Chemistry in the Red-Tailed Phascogale, Phascogale-Calura (Marsupialia, Dasyuridae)

Blood samples were taken from a wild population of red-tailed phascogale Phascogale calura at intervals up until the annual post-mating disappearance of males. While sexual dimorphisms in haematological and blood chemical values were not found, there were detected some age-related changes. Reductions in haematocrit and haemoglobin concentration between mid- and late-July were detected both in females and males but contrary to the finding in another small dasyurid sharing this unusual life history pattern, these decreases in the males could not be described as anaemias. The changes in erythrocyte parameters in the blood of females at about this time conform to the pattern of a macrocytic anaemia which may be nutritionally based. A marked lymphocytopenia and neutrophilia observed at the end of July in males, but not in females, is consistent with other evidence of the development of a stress response.