Allometric and Phylogenic Comparisons of Circulating Leukocyte Concentrations between and within Birds and Mammals

Abstract

The blood concentrations of leukocytes and the major classes of leukocytes were compared across over 200 species of birds and over 300 species of mammals based on phylogenic relations, body weight and diet. The concentration of leukocytes was markedly higher in birds than mammals reflecting elevated concentrations of all major classes but particularly those of lymphocytes, monocytes, eosinophils and basophils. Overall, there were no differences between blood leukocyte concentrations in placental and marsupial mammals. There were differences between leukocytes concentrations within the placental mammals, for instance being lower in mammalian species within the taxa Glires than in Laurasiatheria and Primatomorpha which in turn are lower than in Afrotheria and Xenarthra.