The piranha's fierce reputation is grossly exaggerated. Piranhas are primarily vegetarians for most of the year. They take advantage of the vegetation, fruits and nuts available when the Amazon River rises during the wet season. The river may rise 40 ft (12.2 m) and flood the surrounding forest. During the wet season the natives can swim in the water with no fears of being bitten. When the dry season begins many of the smaller sections of river may dry up to isolated pools. It is then, when food is very scarce, that piranha become predatory. They will devour animals such as snakes, small cattle, capybaras and larger fish. If you have ever seen piranha at the Tennessee Aquarium or on a nature documentary, you may have noticed that you could not see any teeth. Many photos and piranha "props" for horror movies show piranha with their lips removed. Red piranhas are doing well as a species, but their habitat is continually threatened by development. Removal of rainforests results in siltation and fertilizer runoff from agriculture into waterways, both of which decrease water quality.