Scientists discovered a fish that uses its head as a musical drum

Scientists revealed the mystery of unusual skull of marine fish: it can "drum" with ribs for communication

Researchers from Louisiana State University made an intriguing discovery: the mysterious cavity in the skull of the fish Bothragonus swanii is likely used as a kind of "drum" for sound communication. The fish strikes it with specially adapted ribs, creating vibrations. The unique research is published on the LSU website.

Bothragonus swanii is a small bottom-dwelling fish that inhabits the intertidal zone of the northeastern Pacific Ocean. The creature's body is covered with a strong bone armor, making it practically invisible among stones. The main mystery of the species has long been a deep cup-shaped depression in the skull, comparable in size to the fish's brain volume.

The breakthrough in research came thanks to high-resolution micro-computed tomography. Scientists carefully studied preserved specimens of B. swanii and related species. The results were striking: the first pair of ribs in this fish has a completely unusual structure - they are enlarged, flattened and mobile, do not have a rigid connection to the spine, and are connected by tendons to some of the most powerful muscles in the body. These ribs make contact with the bottom of the cranial pit, which is significantly harder than the surrounding walls.

According to the researchers, this unique anatomy allows the fish to produce powerful strikes with its ribs against the inner surface of the cranial cavity, generating vibrations. These vibrations propagate along the sea floor and probably serve as a way of communicating with fellow species that also move along the substrate rather than through the water column. This method of communication can be especially effective in the noisy environment of tidal zones, where ordinary sound signals are lost among the noise of waves and rolling stones.

Although direct observations of such behavior and recordings of the sounds produced have not yet been obtained, scientists consider the proposed mechanism quite plausible and are already planning to test their theory using special underwater acoustic measurements.