The brackish water nourishing Bangladesh's Sundarbans supports a refuge for rare species, but their drinking grounds are getting saline and the world's largest mangrove forest "Sunderbans' is facing serious damage, say experts. Royal Bengal tigers, spotted deer, wild boars, crocodiles and monkeys have been forced to move deep into the forests, away from their usual feeding habitat. The tops of trees are dying every year in the 6,017 sq km Sunderban's area.