Hematological Values of Two Species of Amazonian Caimans, Caiman crocodilus AND Melanosuchus niger

Abstract

The Amazon is one of the most biodiverse regions for crocodilians globally. Four of the five Amazonian caimans species exist in the Brazilian Amazon region. Determining hematological values is essential to provide baseline health and condition data. We evaluated the hematological parameters of free-living specimens of Caiman crocodilus and Melanosuchus niger from the middle Negro River region of Brazil. We captured 18 C. crocodilus and 16 M. niger, which averaged 60.5 ± 13.0 cm and 46.1 ± 18.5 cm in total length, respectively. Blood was drawn using syringes containing 10% EDTA, and blood parameters were determined according to the previously described methodology. The analyzed erythrocyte parameters were similar between the species, demonstrating that, despite presenting different sizes, they have similar strategies for absorption and transport of oxygen in the blood. In the morphological analysis of blood cells, erythrocytes, erythroblasts, thrombocytes, lymphocytes, neutrophils, azurophils, heterophils, and basophils were found and, in the quantification of leukocytes and thrombocytes, it was noted that lymphocytes are the central cells in the blood of Caiman of Amazonian. In the results found for plasma metabolites, no significant differences were observed between glucose and total protein levels. The information generated herein is intended to aid in establishing management plans, conservation, and farming of these species of Caiman Amazonian.