Fish

Not all fish create sound, but those that do create sound by contracting muscles around the swim bladder moving air between sub-chambers of the swim bladder to create a drumming sound, like the one seen below and to the left. They can also create sound by rubbing body parts together. Like the seacat, which rubs its dorsal process against its pectoral girdle.

Fish hear in one of two ways. One way of hearing is by means of an internal ear which contains two parts. The pars superior (upper section), which controls balance, and the utriculus (lower section), which allows the fish to hear. The utriculus is made up of two otoliths (ear stones) that vibrate and stimulate nearby hair cells. A common second way of hearing is through the swim bladder conveying pressure waves to weberian ossicles (small bones). This setup can be seen in the picture below and to the right.