Humpback whales are known virtuosos. Their mating songs are characterized by an impressive duration and complexity. In recent years, however, more and more reports show that they’re not only singing when they find themselves at breeding grounds.
A new study, published at the online journal PLOS ONE, followed ten humpback whales in the Western Antarctic Peninsula. The animals were tagged non-invasively and followed to study foraging and acoustic behavior. On the records of all ten animals background singing was heard, and in two of these recordings, long and complex songs could be discerned (audio files can be found by following the reference below).
In fact, the vocalizations on these recordings were quite similar to the breeding calls with regards to organization and structure. But they weren’t sung at the breeding grounds. No, they were sung during feeding.
This suggests a relatively high degree of behavioral flexibility, or, in other words, the ability to switch between different types of behavior. In this case, that would be the switch from feeding to display behavior. Why choose between feeding and sending out mating calls when you can do both almost simultaneously?
And climate change may play its part in this tale as well. The extent and duration of sea ice cover on and near Antarctica has ondergone major changes recently, and will continue to do so, which affects the distribution of these (and other) whales. Less ice means more open water late in the foraging season. Whales stick around longer, feasting on their aquatic banquet, rather than relocating to warmer breeding waters.
So, breeding behavior on feeding grounds might be a new trend. In whales, at least.
Stimpert, AK, Peavey, LE, Friedlaender, AS, & Nowacek, DP (2012). Humpback Whale Song and Foraging Behavior on an Antarctic Feeding Ground. PloS one, 7 (12) : doi:10.1371/journal.pone.0051214
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