I have mentioned flying fish in order to draw the attention of naturalists to the extraordinary size of their natatory bladder. As this bladder takes up more than half the fish's body volume it probably contributes to its lightness. One could say that this reservoir of air 15 more adapted for flying than swimming. Flying fish, like almost all animals with gills, enjoy the possibility of breathing for a long time with the same organs both in air and in water. They pass much of their time in the air, although flying does not make them less wretched. If they leave the sea to escape from the voracious dolphin they meet frigate-birds, albatrosses and other birds in the air, which seize them in mid-flight. Thus, on the Orinoco banks, herds of capybara (Cavia capybara) rush from the water to escape crocodiles and fall prey to jaguars waiting for them on the banks. I doubt that flying fish leap from the water solely to escape their predators. Like swallows they shoot forward in thousands in straight lines, always against the waves. In our climate, by a clear-water river struck by the sun's rays, we often see single fish, with no reason to fear anything, leap into the air as if they enjoyed breathing air. Why aren't these games more frequent and prolonged with flying fish who, thanks to their pectoral fins and extreme lightness, fly easily in the air?