VIHAR people may be interested in this article from last June:
Gamba, Marco, et al. "The indris have got rhythm! Timing and pitch
variation of a primate song examined between sexes and age classes
<http://journal.frontiersin.org/article/10.3389/fnins.2016.00249/full>."
*Frontiers
in Neuroscience* 10 (2016).
Video teaser: https://twitter.com/Strange_Animals/status/834058613102620673
Abstract:
A crucial, common feature of speech and music is that they show non-random
structures over time. It is an open question which of the other species
share rhythmic abilities with humans, but in most cases the lack of
knowledge about their behavioral displays prevents further studies. Indris
are the only lemurs who sing. They produce loud howling cries that can be
heard at several kilometers, in which all members of a group usually sing.
We tested whether overlapping and turn-taking during the songs followed a
precise pattern by analysing the temporal structure of the individuals'
contribution to the song. We found that both dominants (males and females)
and non-dominants influenced the onset timing one another. We have found
that the dominant male and the dominant female in a group overlapped each
other more frequently than they did with the non-dominants. We then focused
on the temporal and frequency structure of particular phrases occurring
during the song. Our results show that males and females have dimorphic
inter-onset intervals during the phrases. Moreover, median frequencies of
the unit emitted in the phrases also differ between the sexes, with males
showing higher frequencies when compared to females. We have not found an
effect of age on the temporal and spectral structure of the phrases. These
results indicate that singing in indris has a high behavioral flexibility
and varies according to social and individual factors. The flexible
spectral structure of the phrases given during the song may underlie
perceptual abilities that are relatively unknown in other non-human
primates, such as the ability to recognize particular pitch patterns.
--
Cognitive Science Programme
UCD School of Computer Science and Informatics
UCD: http://csweb.ucd.ie/AcademicProfile/FredCummins
<http://www.csi.ucd.ie/users/fred-cummins>
Personal: http://pworldrworld.com/fred
Twitter: @fcummins
