Dolphins doesn't have vocal cords, on the other hand generating
sounds is a complex system of shrieks, Squeals, groans, trills, and clicks are generated
by their sphincter muscles inside the blowhole. <span>The
sphincter muscle is a circular </span>muscle<span> that usually retains contraction of a natural
body passageway or opening, which relaxes as required by normal physiological
functioning</span>
