Scientists have made the unexpected discovery that male fin whales exchange songs. The findings are surprising considering that prior to this research, it was believed that fin whales stick to just one song pattern that is unique to the males of each group.
The study, which is published by Frontiers, suggests that the whales sing multiple songs that are spread throughout the ocean by migrating individuals.
The fin whale, the world’s second largest mammal, is listed as endangered under the Endangered Species Act. Up until several decades ago, their numbers were greatly depleted by commercial whaling. Today, the biggest threat to fin whales comes from vessel strikes.
By studying their complex singing behavior, scientists gain new insight into how fin whale populations move and evolve over time, which can help efforts to protect them.
“There is still a lot of uncertainty around the fin whale population size and structure in the North Pacific, and so learning about the song could help us understand population dynamics in this region much better,” said Dr. Tyler Helble of the Naval Information Warfare Center Pacific.
“Male fin whales in the Pacific sing just two very low notes, which are produced in different rhythms to create song. Previously, some marine mammal scientists thought that fin whales each sang a single pattern of notes, which was found only within their specific group and region. Our research indicates that fin whale song is more complex than this.”
Over six years, the team used underwater microphones, or hydrophones, to record the songs and locations of 115 whale encounters near Kauai, Hawaii.
“The sound is recorded on multiple hydrophones, allowing us to triangulate on the signal and formulate a position for the animal,” said Dr. Regina Guazzo. “By showing that different song patterns were coming from the same location, we demonstrated that these were likely made by the same individual.”
The recordings captured five main song patterns. Some of the songs were found to be unique to this region, but others shared similarities with song patterns recorded several years earlier in populations off the northwest coast of the United States.
“When a new whale song is recorded in a region, researchers often read it as a signal that a new group or individual has arrived from a different part of the world,” said Dr. Guazzo. “However, this study suggests that these new song patterns may have been picked up by a local whale on his migratory travels, in a process of cultural transmission between groups from different regions”.
The scientists could use additional methods of monitoring to confirm whether the fin whales recorded in Hawaii are from a single group or multiple converging groups.
“Visual identification, genetic analyses, or long-duration tags could be used to determine where these whales go when they are not singing off Kauai,” said Dr. Helble.
The study is published in the journal Frontiers in Marine Science.
By Chrissy Sexton, Earth.com Staff Writer