Fin whale in Sea of Cortez, Mexico. ©Tom Kieckhefer
Fin whales are dark gray with a distinctive pale chevron on their back and a white lower right jaw and dark lower left jaw. They grow to 24 meters (80 ft) in length. Fin whales are distributed worldwide, and are usually found in higher latitudes in the summer. Fin whales produce low frequency vocalizations that are called “20-Hz pulses” even though they are usually downward sweeps in frequency from about 30 to 15 Hz. Their vocalizations can be as loud as 184-186 underwater dB, making them one of the most powerful biological sounds in the ocean. Scientists use these loud calls to study their distribution. Recent research in the Gulf of California, Mexico, shows that fin whale vocalizations are only produced by male whales. These results support the hypothesis that these vocalizations function as male breeding displays, attracting females from great distances to concentrations of prey that the male has found.