02579nas a2200265   4500008004100000022001400041245009500055210006900150260001600219520172900235653002501964653001101989653002802000653002502028653002402053100002402077700002002101700001902121700001702140700001902157700002002176700001602196700001502212856008602227       2018                        eng d  a1045-224900aAcoustic stability in hyrax snorts: vocal tightrope-walkers or wrathful verbal assailants?0 aAcoustic stability in hyrax snorts vocal tightropewalkers or wra  cOct-10-20193 a<p>The source-filter theory proposes that information on caller properties is communicated through acoustic qualities, as physical state and performance ability are reflected in the voice. Vocal stability, manifested through harshness, is especially intriguing and has rarely been explored although harsh sounds are prevalent in nature. Male rock hyraxes (Procavia capensis) produce loud complex calls that we term songs. Only the calls of older, socially dominant males include a harsh sound termed snort. As snorts are the rarest element in songs, we hypothesized that high-quality snorts are difficult to produce, and that their quality consists in the ability to maintain smoothness throughout this low-pitched, harsh call. We quantified harshness by measuring periodicity deviations and expected to find a link between social parameters (residence, rank, and weight) and the ability to produce longer, smoother snorts. In addition, we presumed that if calls are used as vocal contests, conspecifics would avoid answering songs that exhibit a higher acoustic ability than their own songs. We found that in wild hyrax songs, snort harshness was associated with both weight and social rank, but in opposite directions. Heavier males produced smoother snorts and higher-ranked individuals produced harsher snorts, possibly indicating aggressiveness. Playback experiments showed that longer and harsher synthetic snorts, inserted into natural songs, reduced conspecific answer rates. Snorts may communicate complex information on hyrax weight and dominance by means of element length and harshness. Our present results provide a stimulating insight into the understanding of acoustics in mammalian vocal communication.</p>
10ainner arousal theory10ajitter10anonlinear vocalizations10asource-filter theory10avocal communication1 aWeissman, Yishai, A1 aDemartsev, Vlad1 aIlany, Amiyaal1 aBarocas, Adi1 aBar-Ziv, Einat1 aShnitzer, Inbar1 aGeffen, Eli1 aKoren, Lee  uhttps://academic.oup.com/beheco/advance-article/doi/10.1093/beheco/ary141/514236302522nas a2200253   4500008004100000022001300041245008400054210006900138260001600207300001100223490000800234520175500242653001801997653002502015653002302040653003702063653001902100653001702119100001502136700002002151700001502171700001602186856006602202       2017                        eng d  a0003347200aMale hyraxes increase countersinging as strangers become ‘nasty neighbours’0 aMale hyraxes increase countersinging as strangers become nasty n  cJan-12-2017  a9 - 140 v1343 a<p>Many territorial animals interact less aggressively with neighbours than with strangers, a phenomenon known as the &lsquo;dear enemy&rsquo; effect, although some species show the opposite behaviour. Rock hyraxes, Procavia capensis, are social mammals that communicate via a rich acoustic repertoire. Male hyraxes produce elaborate advertisement calls (i.e. songs) both spontaneously and in response to occasional attention-grabbing events (e.g. pup screams, agonistic interaction), as well as to conspecific male songs. When replying to conspecific songs, male hyraxes tend to respond more to familiar males than to strangers, reflecting the &lsquo;nasty neighbour&rsquo; effect. Our study relates to the general question of why some species respond aggressively towards neighbours, while others are more aggressive towards strangers. We hypothesized that male hyraxes eventually familiarize themselves with a stranger, subsequently perceiving its intentions as highly threatening and deserving of a vocal response. To simulate the presence of a stranger in the area we exposed wild hyrax groups to playbacks of natural songs of un- familiar hyraxes. Male rock hyraxes became more likely to reply to a stranger&#39;s song over time, but this was independent of the number of times they heard the song. This suggests that either (1) the threat presented by a stranger increases when it is no longer perceived as transient or (2) because listeners do not physically encounter the stranger, they perceive replying aggressively as a low-risk response. Our work implies that species may demonstrate a range of condition-dependent behaviours instead of a dichotomy between the &lsquo;nasty neighbour&rsquo; and &lsquo;dear enemy&rsquo; strategies.</p>
10aadvertisement10aanimal communication10afloating territory10aneighbour-stranger relationships10asocial mammals10avocalization1 aGoll, Yael1 aDemartsev, Vlad1 aKoren, Lee1 aGeffen, Eli  uhttp://linkinghub.elsevier.com/retrieve/pii/S000334721730324X