As described in a recently published paper in Biology Letters, the Philippine Tarsier (Tarsius syrichta) has been found to communicate through extremely high pitched vocalisations in the ultrasound domain, undetectable by human ear. These presumed mute primates baffled primatologists… How can such lack of calls be observed when closely related species are clearly dependent on frequent vocal signals within the group? However the mystery was solved when upon further inspection, these little guys could be heard communicating among the highest frequency levels detected from any terrestrial mammals. It is now thought the extremes of these calls could allow conspecifics to communicate whilst remaining undetected by predators or prey and/or allow individuals to be more easily heard through background noise.
(Ramsier et al. 2012) Primate communication in the pure ultrasound.
DOI: 10.1098/rsbl.2011.1149
stacja tłuszcz said:
very interesting article, i’ve always wanted to write my own blog but i don’t have much time,
regards from st
Mike Potter said:
I love Tarsiers. They are so strange yet intriguing. They are almost unclassifiable, as they possess both anthropoid and prosimian characteristics. This communication system adds to their uniqueness.
Corrugated cardboard said:
I simply love reading about such amazing scientific facts. It would be so great to hear the primates talking privately some time.
DDeden said:
Owls can rotate their heads 270 degrees and have air sacs surrounding their cervical arteries/veins to protect against anoxic strokes (reduced oxygen flow to brain during swivelling of head while body remains immobily perched on branch). I suspect tarsiers and perhaps some small insectivorous New World monkeys and maybe the Ayeaye lemur have these air sacs with associated high-pitched vocalizations, and that the much larger laryngeal air sacs in great apes are derived from them (gradually enlarging duringand after the “upright-ape” Morotopithecus stage of 20ma), which I think enlarged because of advantageous volume in calling in thick rainforest sub-canopies, but perhaps also functionally for upper-body enhancement in male dominance competition on the ground and for improved face-up position flotation (wade-foraging in swamps for floating vegetation (Ndoki swamp gorillas finger-rake floating high-protein hydrocharis/frogbit). Humans occasionally develop pathological laryngeal air sacs from calling/glass blowing, but not normally. The Australipithecus Lucy and Selam had them, while Homo species apparently lacked them, perhaps indicating a switch from tree-branch bowl nests to ground-dwelling dome huts, ground foraging (nuts, tubers, melon, bush-berries) and submerged dive-foraging (shellfish).
DDeden said:
Per this article on owl air sacs
http://www.bbc.co.uk/news/science-environment-21279609#
(all birds have numerous air sacs, some connect lungs to pneumatic bones, etc.)