[61 ] As with fish and turtles on a coral reef, hippos occasionally visit cleaning stations and signal, by opening their mouths wide, their readiness for being coaching cleaned of parasites by certain species of fishes. A hippo closes its nostrils when it submerges into the water. A hippo sleeping underwater rises and coaching breathes without waking. :4 The process of surfacing and breathing is automatic.
The young have to breathe every two to three minutes. Over prolonged periods, hippos can divert the paths coaching of swamps and channels. [56 ] Because of their size and their habit of taking the same paths to feed, hippos can have a significant impact on the land across which they walk, both by keeping the land clear of vegetation and depressing the ground. These deposits have coaching an unclear ecological function.