Blood Oxygen Stores in the File Snake, Acrochordus granulatus, and in Other Marine Snakes

Abstract

Blood oxygen stores were determined in the file snake, Acrochordus granulatus, and three other species of marine snakes (Cerberus rhynchops, Emydocephalus annulatus, Laticauda colubrina). Relative blood volume (% of body mass), plasma volume, and blood cell volume increased in proportion to body size in A. granulatus. Relative blood volume ($\bar{X} = 13.3\%$), hematocrit ($\bar{X} = 41\%$), and blood oxygen capacity (BOC) ($\bar{X} = 16.22$ vol%) far exceeded values for the other species examined, and are exceptionally large for reptiles. However, BOC is no greater than expected for reptiles with similar hematocrits. Blood oxygen stores are much larger in A. granulatus than in other reptiles. Immense blood oxygen stores, in combination with other specialization for prolonged use of stored oxygen, may allow A. granulatus to submerge for longer periods than other marine snakes. A suite of diving adaptations that is different from that of typical marine snakes may enable A. granulatus to exploit environment...