Spring 2012

Prof: Tiny Primates Communicate with Ultrasonic Private Channel

Marissa RamsierMarissa Ramsier (Submitted Photo)

HUMBOLDT STATE ANTHROPOLOGY LECTURER and alumna Marissa Ramsier (‘03, Anthropology) has garnered international media attention for a recent paper published in the Biology Letters of London’s distinguished Royal Society.

In her research, which has been publicized on MSNBC, Discovery.com, National Public Radio and elsewhere, Ramsier discovered that the tarsier, one of the world’s smallest primates, probably has an ultrasound warning system within its social groups.

Ramsier and colleagues in the field conducted research with the elusive Philippine tarsier using state-of-the-art recording technology. Recordings made so far indicate that the tarsier’s vocalizations may represent a “private channel” of communication via ultrasonic signals. They are undetectable either by the human ear or by many of the monkey’s prey and predators.

Ramsier expects further research and analysis to determine what advantages the tarsier derives from its specialized sensory adaptation. But the evidence she and her colleagues have collected to date on the Philippine Islands have broader implications for all vertebrates.

That is because comparatively few mammals send and receive pure ultrasonic signal.

Advances in non-intrusive recording technology now enable researchers to generate audiograms of wild animals without compromising their way of life or habitat. Ramsier and her colleagues expect future research to provide insights into the basic attributes that would promote high-frequency hearing in all vertebrates.