Adapted from Clarke 1978
Located in the complex head of the sperm whale, the spermaceti organ’s function is not completely clear. The primary hypothesis is that this organ plays a role in focusing emitted sounds and that it may affect buoyancy (Whitehead and Rendell, 2004). The spermaceti organ is made of two sacs known as the junk and the spermaceti sac. Both sacs are filled with oil although the oil in the junk is denser. The organ is like a “reverberation and sound-focusing chamber” and plays a major role in producing signals for echolocation (Smith, 2005). Larger spermaceti organs have longer impulse intervals of sound. Larger males with larger spermaceti organs have so much stored fat in this region that cannot be accessed in time of need making them more likely to starve and not as fit as smaller individuals. This low fitness explains why females stay away from males who have longer impulse codas and might be an explanation of why the largest males do not seem to mate (Smith, 2005).