How does a piranha breathe?

The king cobra breathes by it's lungs.The air passes from its nasal orifice through trachea to longer left lung.(The smaller right lung is rudimentary one.).The lung has become longer owing to its body shape.Thus storing a greater volume of air the snake could hold its breath for a long time while swallowing a prey.On the other hand as the snakes are cold blooded their body metabolism is very less requiring less amount of air and that too in greater intervals. The king cobra breathes by it's lungs.The air passes from its nasal orifice through trachea to longer left lung.(The smaller right lung is rudimentary one.).The lung has become longer owing to its body shape.Thus storing a greater volume of air the snake could hold its breath for a long time while swallowing a prey.On the other hand as the snakes are cold blooded their body metabolism is very less requiring less amount of air and that too in greater intervals.