Cultural revolutions reduce complexity in the songs of humpback whales.

摘要: Much evidence for non-human culture comes from vocally learned displays, such as the vocal dialects and song displays of birds cetaceans. While many oscine use complexity to assess male fitness, role in humpback whale (Megaptera novaeangliae) is uncertain owing population-wide conformity one pattern. Although songs change gradually each year, eastern Australian population also completely replaces their every few years cultural 'revolutions'. Revolutions involve learning large amounts novel material introduced Western population. We examined two measures structure, entropy, over 13 consecutive years. These aimed identify information content processes whales. Complexity was quantified at hierarchical levels: entire sequence individual sound 'units' stereotyped arrangements units which comprise a 'theme'. increased evolved time but decreased when revolutions occurred. No correlation between entropy estimates suggests that changes may represent embellishment could allow males stand out amidst conformity. The consistent reduction during potential limit social capacity