Tiny primate 'talks' in ultrasound

Feb 08, 2012 by Marlowe Hood
Two tarsiers cling onto trees in a wildlife sanctuary in the central Philippine island of Bohol in 2006. One of the world's smallest primates, the Philippine tarsier, communicates in a range of ultrasound inaudible to predator and prey alike, according to a study published Wednesday.

One of the world's smallest primates, the Philippine tarsier, communicates in a range of ultrasound inaudible to predator and prey alike, according to a study published on Wednesday.

No bigger than a man's hand, Tarsius syrichta can hear and emit sounds at a frequency that effectively gives it a private channel for issuing warnings or ferreting out crickets for a nighttime snack, the study found.

Only a handful of mammals are known to be able to send and receive vocal signals in the range, above 20 (kHz), including some whales, and a few of the many species of bats.

And few of these can squeal, screech or squawk at the same sonic altitudes as the saucer-eyed tarsier, which up to now had been mistakenly described as being "ordinarily silent," researchers found.

Fact file on the Philippine tarsier, one of the world's smallest primates, now discovered to be able to communicate in ultrasound frequencies, according to a study published on Wednesday

Its finely-tuned ears are capable of picking up frequencies above 90 kHz, and it can vocalise in a range around 70 kHz.

By comparison, humans generally can't hear anything above 20 kHz, and a dog whistle is pitched to between 22 and 23 kHz.

A team of scientists from the United States and the Philippines led by Marissa Ramsier of Humboldt State University in California gathered their inaudible results in two ways.

First they captured six of the docile nocturnal creatures and placed them inside custom-build sound chambers to test their sensitivity to high-pitched sounds.

After the experiments, the rare and were returned unharmed to their , on the Philippine island of Mindanao.

A tarsier eyes a cricket in a widlife sanctuary in the central Philippine island of Bohol in 2006. One of the world's smallest primates, the Philippine tarsier, communicates in a range of ultrasound inaudible to predator and prey alike, according to a study published Wednesday.

To measure the frequency of the tarsier's ultrasound chatter, the researchers recorded another 35 specimens in the wild.

"The minimum frequency of the call -- 67 kHz -- is the highest value of any terrestrial mammal, excluding bats and some rodents," said the study, published in the British Royal Society's Biology Letters.

What advantages do the tarsier's high-end vocal acrobatics confer? There are several, the researchers suggest.

One is being able to sound a silent alarm.

"Ultrasonic calls can be advantageous to both the signaller and receiver as they are potentially difficult for predators to detect and localise," the researchers explain.

A newborn tarsier is cuddled by its mother after giving birth in captivity in the Philippine town of Saranggani in 2002. One of the world's smallest primates, the Philippine tarsier, communicates in a range of ultrasound inaudible to predator and prey alike, according to a study published Wednesday.

The tarsier's exceptional hearing may also facilitate acoustic eavesdropping on noises emitted by prey, which range from and cockroaches -- their staple diet -- to the occasional moth, katydid or hatchling bird.

Finally, the study speculates, being able to communicate in ultrasonic ranges filters out all the low-frequency "noise" and hubbub of a tropical environment.

Tarsier's have five-digit hands that eerily resemble -- in emaciated form -- their human counterparts.

Lacking the typical "night vision" of other nocturnal creatures, they also have -- in relation to their body size -- the largest eyes of any primate on Earth.

Explore further: Acoustic methods to com­pli­ment cur­rent whale mon­i­toring efforts

add to favorites email to friend print save as pdf

Related Stories

Scientists discover ultrasonic communication among frogs

May 11, 2009

(PhysOrg.com) -- UCLA scientists report for the first time on the only known frog species that can communicate using purely ultrasonic calls, whose frequencies are too high to be heard by humans. Known as ...

Moth ears are activated by movement the size of an atom

Oct 20, 2011

(PhysOrg.com) -- Moths are so finely tuned to the ultrasonic calls of predatory bats that the nerve cells in their ears are activated by displacements of the eardrum the size of a small atom, according to ...

Roaring bats

Apr 30, 2008

Annemarie Surlykke from the Institute of Biology, SDU, Denmark, and her colleague, Elisabeth Kalko, from the University of Ulm, Germany, studied the echolocation behavior in 11 species of insect-eating tropical bats from ...

Researchers studying how singing bats communicate

Oct 18, 2007

Bats are the most vocal mammals other than humans, and understanding how they communicate during their nocturnal outings could lead to better treatments for human speech disorders, say researchers at Texas A&M University.

Recommended for you

Breakthrough in coccidiosis research

22 hours ago

Biological researchers at the Royal Veterinary College (RVC) are a step closer to finding a new cost-effective vaccine for the intestinal disease, coccidiosis, which can have devastating effects on poultry ...

Vietnam's taste for cat leaves pets in peril

Jul 28, 2014

The enduring popularity of "little tiger" as a snack to accompany a beer in Vietnam means that cat owners live in constant fear of animal snatchers, despite an official ban.

User comments : 0