Spectacle caiman linger below, waiting for a meal to fall out of the sky. When rivers finally reach the sea they slow down, release their sediment and build deltas. In Bangladesh the Ganges and Brahmaputra rivers join to form the world's biggest. Every year almost 2,000 million tonnes of sediment eroded from the Himalayas is delivered to the ocean. At the delta's mouth the largest mangrove forest in the world - the Sundarbans. These extraordinary forests spring up throughout the tropics in these tidal zones where rivers meet the sea. Crab-eating macaques are mangrove specials. In Indonesia these monkeys have adopted a unique amphibious lifestyle. They fish out fallen food. The troop also uses the waters to cool off during the heat of the day. But the channels are also the playground for restless young macaques.


眼镜凯门鳄在下面静待，等待从天空中掉下的食物。当河流最终流入大海时，它们放慢流速，释放沉积物，形成三角洲。在孟加拉，恒河和布拉马普特拉河会合之后冲积出世界上最大的三角洲。每年从喜马拉雅山区冲刷下来的沉积物达20亿吨，它们都被带到了印度洋。在这片三角洲河口，生长着世界上最大的红树林这种特殊的树木在河流与大海交汇的潮汐区生长。食蟹猴是红树林里的专家。在印度尼西亚，这种猴类有独特的两栖本领。他们可以打捞树上落下的果子。它们在天热的时候还会用水来冲凉。但树下也是一刻不停的小猴们的乐园。