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http://www.shougakukin.jp/info/oakley.html Humpback Whale Ac
Humpback Whale Acoustics Collaboration
Though the songs of humpback whales have been studied extensively for many years, research into their other communicative sounds (known collectively as 'social sounds') is fairly new. Humpback whale social sounds comprise two types of http://www.shougakukin.jp/info/oakley.html sound; オークリー アウトレット sounds produced by surface behaviours (such as breaching or slapping the surface) and vocal calls.
Most of the current research into humpback whale social sounds has been on the east Australian population during their southern migration. The catalogue of vocal sounds they use is extremely varied, comprising of at least 34 different sound types ranging from low frequency 'snort'like sounds to high frequency 'bird chirp'like sounds (Dunlop et al. 2007). Vocal sounds, as well as surfacegenerated sounds, are thought to be used in many different contexts; as songlike signals may be used for sexual selection, other signals may be used to maintain contact between group members (such as cows with calves), to provide information on sex and location of the signaller and/or to mediate competition between males. Dunlop et al. 2008) has provided many testable hypotheses but much more work is needed to elucidate the specific function or each sound type.
Much of the research into large whale communication centres on the effects ニューバランス 店舗 of anthropogenic noise. However, before understanding the effects of anthropogenic noise on their communication, we must first understand how they communicate in noise. A recent study found that humpback whales tend to change from primarily vocal communication to primarily surfacegenerated sound production in higher winddominated noise levels (Dunlop et al. 2010). However, the presence of other singers has also been found to have a significant effect on vocal behaviour (Dunlop et al. submitted). Therefore, the both the noise environment and the social environment have complex effects on humpback whale communication behaviour (Project leader: Rebecca Dunlop).
Humpback whale social sounds are also the subject of research by PhD student Mindi Rekdahl, who is in the final stages of her PhD.
Temporal stability of the vocal communication repertoire of humpback whales
The aims of this project were to investigate the temporal stability of the social call repertoire and the influence from the highly variable song display and to investigate the complexity of the social call repertoire by investigating the use of social calls within bouts.
To investigate temporal stability in the social call repertoire of east Australian humpback whales, and the relationship with the song repertoire, social calls and song were isolated from moored hydrophone array recordings from three time periods over eleven years. Only a small proportion of the repertoire persisted over the study period and most call types in the repertoire were relatively rare and either found to change in a similar fashion to song ( unit social calls) or only found in one or two years. Although the call types were エアジョーダン スニーカー easily classified into distinct types, all varied in at least some of the measured call parameters across the study period. The lack of a clear directional trend suggests that call modifications are not permanent, but reflect the graded nature of calls in changing social environments.
The structure and complexity of social call use by humpback whales was explored by investigating call use within bouts, and bout use in different social contexts from digital acoustic tag (DTAG) recordings. The distribution of calls into bouts was investigated by defining a bout criterion, and the structure of calls within bouts was investigated by comparing call transition frequencies. Call bouts were found to be common, and bouts were produced more often during joining interactions. Although call bouts lacked エアジョーダン レディース the stereotyped structure of song, there was order to how calls were combined within bouts, suggesting that humpback whales may have the potential for greater communication complexity エアジョーダン11 コンコルド than previously thought.
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