Monkey known for being silent is actually a chatterbox - using ultrasound that predators can't hear

By TED THORNHILL

Hear hear: The Philippine Tarsier speaks in ultrasound

The Philippine Tarsier monkey is known for having huge saucer eyes, being incredibly small and not saying much at all. But now it’s been revealed as a real chatterbox – in ultrasound.
Researchers from Humboldt State University in California in fact found that the ‘minimum frequency’ of its call is 67kHz - higher than any land-based animal bar rodents and some bats – and occasionally rising to 70kHz.
Anything above 20kHz is inaudible to a human, with dogs able to detect sounds pitched up to 23kHz.

The Philippine Tarsier factfile

The Tarsier’s ears are able to pick up sounds at a distinctly squeaky 90kHz.
The upshot of all this is that the dinky nocturnal primates – which are no bigger than a human hand and weigh around 120grams – effectively have a secret language that they can use to warn each other of predators.
The researchers said: ‘Ultrasonic calls can be advantageous to both the signaller and receiver as they are potentially difficult for predators to detect and localise.’

Handy: The Tarsier's high-pitched abilities means that it has a secret way of communicating

They can also tip each other off about nearby prey, typically crickets, moths and cockroaches, and cut out distracting low-frequency jungle noises.
Whales and cats are also able to communicate in the ultrasound range.
The study was published in the British Royal Society’s Biology Letters.

source: dailymail