Fig. 2. Changes in the blood flow to major organs, the brain and retina in Weddell seals during diving. The normal blood flow (pale blue) and the blood flow during diving (dark blue) to the pancreas and liver, heart, lungs, retina, cerebellum and cortex. There is a substantial reduction in blood flow to the pancreas, liver and heart but not to the lungs, retina, cerebellum and cortex. Adapted from Schmidt-Nielsen (Schmidt-Nielsen, 1998); data from Zapol et al. (Zapol et al., 1979).