Frogs eat insects and each other. Plants provide homes for insects and animals and depend on those animals to disperse their seeds. Leaf cutter ants provide an excellent example of a symbiotic relationship. Leaf cutters are herbivores that can't digest cellulose . Fecal fluid from worker ants contains amino acids and enzymes that fertilize the fungus and break down the leaf proteins into smaller protein molecules that ants can digest.
Adaptation is another key factor in survival.
Pink dolphins, about twice as large as the other species of river dolphins that inhabit the Amazon, are adapted to their environment in some interesting ways. The murky water has diminished their eyesight but sharpened their echolocation abilities, while the water's warmth has eliminated the need for body fat. Superstition has also contributed to the pink dolphins' survival. Local lore has it that anyone who hunts or harms them can become ill or die, so everyone leaves them alone. The number of people living in or near the rain forests is increasing.